Respuestas al mensaje #1,533

It depends a lot on your genetics of your skin, but if you are the kind of guy who gets fat easily (endomorph) you should do chest exercises...

Yes. I have them on the inside of my upper thighs, from doing squats. Edit: arm shot. These are from ten years ago and have faded somewhat with time.

In addition to the other answers, these can occur during puberty too because of growth spurts, though they'll fade with time.