I have pretty much decided that I would need biceps like Arnold Schwarzenegger to combat the loose skin on my arms.
My suggestion is to cover your arms with tattoos, that way people won't notice
Seriously though, doing upper body and lower body strength training may help you build muscle which may (or may not) help.
Over time some of the skin may go back to where is belongs or you may be looking at having it removed surgically if it is bothersome.
Best of luck Spark Friend!