if your muse could change one thing about their appearance, what would it be?
this is going to be a long-winded answer. sorry!
when he was younger and scrawny, he always felt too big for his body — like his vision of himself did not quite align with the rest of the world’s. he could picture himself: the crooked edge of his nose, the too-short fingernails, the cuts, the shag of his hair. but his clothes were always too big and his anger always too broad for his form. so when he got the serum, for a moment, it was finally like he was big enough to fit his features, to fit his insides. he felt aligned and strong and excited.
he would break some ribs and laugh as they healed. he’d get a cut or get grazed by a bullet and feel high off how fast his body healed. nothing stuck to him. none of his old scars were there. his callouses were gone. all those marks from past sicknesses weren’t there either. it seemed like even the crook in his nose was a little straighter, although not fully healed. and then it hit him: nothing stuck to him.
he woke up seventy years later, looking like he did back in world war ii. years went by. he still looked like that. didn’t matter what happened. didn’t matter how he changed inside — he still looked the same. and it’s led to this really odd issue of, once again, his perception of himself no longer aligns with how he looks ( or how other people view him ). he’s got some weird body issues of just…having trouble recognizing himself in a mirror. he tries not to think about it.
so, to ( finally ) answer your question: if there was one thing steve rogers could change about his appearance, it would be to look a little older and age with the years. to have a few of those scars stick. to actually, for once, change in some way. because they didn’t think about that when they shot him up with the serum, and if there’s one thing he’s afraid of, it’s not turning gray, not moving forward, just being stuck as an old, perfect fossil.