For a man who once weighed 980 pounds and had already lost 650 of them, the loss of 50 more — the amount that vanished after Paul Mason’s nine-and-a-half-hour operation last month — might not seem like a big deal.  But Mr. Mason, who at his heaviest was known informally as the world’s fattest man, had been all but crippled by those 50 pounds, loose skin that hung over his body like melted wax over a candlestick. And so its absence has made all the difference.  It means he can get out of his wheelchair and go for a walk. It means he can take a shower standing up. It means that his knees no longer ache, that he can slip easily in and out of bed without feeling like he has anvils strapped to his thighs, that he has sensation in his feet, and that when he puts his pants on he does not have to contend with an apron of extra flesh flopping from his waist to his thighs.  “It seems a bit weird,” Mr. Mason said recently. “I’d got so used to maneuvering my excess skin out of the way.”  It took a lot of planning and a great deal of good fortune for Mr. Mason, who is 54 and comes from Ipswich, England, to have the operation at all. Lenox Hill Hospital on the Upper East Side of Manhattan, where it was performed, waived all its fees. So did the four plastic surgeons who operated, and so did the general surgeon, the anesthesiologist and the nurses who took part.  Mr. Mason’s bills would probably have exceeded $250,000, said Dr. Jennifer Capla, the surgeon who led the team at Lenox Hill.  It took Mr. Mason a long time to get as fat as he was, and it has taken him a long time to try to shed all that weight and find a life approaching normalcy. Bullied, sexually abused and unloved as a child, he said he dulled his feelings with more and more food. Eventually he got into bed and kept eating until he became too heavy to get out. Finally, spurred by a sympathetic therapist, he had gastric bypass surgery, in England, overhauled his diet and dropped to 350 pounds.  This latest operation, in early May, was the culmination of two years of effort by Dr. Capla, a plastic surgeon in Manhattan who learned of Mr. Mason’s affliction when her mother, Judith Capla, also a doctor, saw news reports about him. Dr. Jennifer Capla specializes in loose-skin removal after extreme weight loss, but she had never operated on anyone whose weight loss was so extreme.  It was a complex case, and not only because of the logistics or the simple fact that there was more of Mr. Mason to remove than there usually is for patients in his position. His excessive weight had left him with a host of medical issues, including a history of blood clots, and Dr. Capla brought in three other plastic surgeons to assist in the operation: Dr. Wojciech Dec from Lenox Hill, and Dr. J. Peter Rubin and Dr. Joseph Michaels, former colleagues in Pittsburgh and Maryland.  The biggest challenge was presented by the many blood vessels in the skin to be removed. There were hundreds, each about four times normal size, Dr. Capla said, and they had to be identified and then individually cauterized and tied or clipped, a process that took hours. “If you miss just one, he could bleed out,” she said.  It took the doctors more than four hours to remove the first piece of skin, from the area around Mr. Mason’s midsection, and there was a feeling of triumph as they finally cut it away and laid it out on a table. The anesthesiologist monitoring Mr. Mason’s vital signs said that when that piece was removed, his CVP, which measures how hard the heart has to work to pump blood, fell instantly.  In the end, the surgeons excised about 25 pounds from Mr. Mason’s midsection and perhaps 25 to 30 from his legs, much of it concentrated in his right leg, which was so swollen with fluid that he was unable to walk more than a few steps. They went through about 140 suture packs, each representing about eight or nine sutures. “We’re talking about eight feet of incisions,” Dr. Capla said.  After he left the hospital, Mr. Mason recuperated for a few weeks in a Midtown Manhattan hotel room paid for by another benefactor, a businessman from Illinois.  The businessman, who did not want to be identified, told Mr. Mason that he was donating the money in honor of his late mother, who had also struggled with her weight, said Mr. Mason’s fiancée, Rebecca Mountain. (They met when she read about him online and got in touch with him through Facebook.) “His mom was really heavy and he felt a connection with what Paul was going through,” Ms. Mountain said.  Back at home now in Orange, Mass., where Mr. Mason has moved to be with Ms. Mountain, the couple still faces many obstacles.  Though her cat-furniture business is beginning to take off, Ms. Mountain said, she does all the work herself and she struggles to keep up with orders. Money is very tight, and there are issues surrounding Mr. Mason’s immigration status.  His visa is scheduled to run out in a few months. He and Ms. Mountain cannot get married and live together in the United States until she can prove to the authorities that she has the means to support him as well as herself, she said.  “Somehow or other he will find a way to stay, and then he can maybe take a part-time job in town,” she said.  “Stacking shelves, whatever I can do,” Mr. Mason said. “I don’t mind.”  Down the line, he hopes to have at least one more operation, to remove the flesh that still hangs from his upper arms. But that is in the future. At the moment Mr. Mason is just adjusting to his new self, emerging into a different life; one with more possibility.  He does not get as tired as he did just after the operation and is now walking his dog, Duke, in the garden every morning, something that was unthinkable before. He and Ms. Mountain have done some gardening, and are starting to make plans to grow vegetables and fruit.  The other day, they went to the movies. It seems like a small thing, but it wasn’t.  “I was able to sit in a cinema seat for the first time in 30 years and hold hands and cuddle, like couples do,” he said.  A version of this article appears in print on June 15, 2015, on page A15 of the New York edition with the headline: Down From 980 Pounds, With New Battles to Wage. Order Reprints| Today's Paper|Subscribe
For Paul Mason, who dropped 700 pounds, the last 50 made the biggest difference, when a team of surgeons in Manhattan removed his excess skin.