Re: red bumpage/stretch marks
If the red bumps are of the same type as the ones I used to get (back when I would shave for my gf), they are actually acne. Buy some clean&clear acne medication, rub it on, and let it dry before putting clothes on. This should clear things up. Also lay off running for a few days after shaving.
As for the stretch marks, I have no idea. But its been my experince that girls don't care very much about those, if at all.