hmm.. I was just thinking if you had shapely deltoids/shoulder muscles it would help pull up some of the skin to the top side...? I guess also if you work the bicep it will add muscle tone around the bicep area the skin will have to cover too... this is why I'm starting my strength training now! I'm not going to wait till I've lost some fat with cardio and diet. Cuz by the time I do that I want to have nice shapely muscles under it! So my recommendation is to focus more on the
Triceps &
Deltoids and lightly train the bicep as well. (I've found I don't need to train my bicep as much to see results). Make sure you work all three heads of the triceps and do diff delt exercises because I think there are like 4 muscles in the deltoids (shoulders). And the one that comes down the side of your shoulder i think a Lateral Raise with dumbells will work that.
okay after reading my response I realize I didn't give you a specific exercises so I found some on one of my favorite sources of muscle building exercises... Those hyperlinks go to M&F Hers website. also check out other fitness magazines like Shape's, Fitness's, & even Self's websites for great at home & gym workouts for those!