Wrap Me Up in Bubble Wrap

Peter loses his powers.
Not all at once, but it was a gradual decline that took a toll on his body. At first, he thought maybe he was just sick. Maybe it was just something he'd get over.

Injuries took a bit longer to heal.
His senses weren't quite as sharp.
His reflexes slowed.

It didn't take much longer for Peter to be forced to hang up his suit.