As has been said here before, what’s in the past is in the past. It’s very difficult numerically to make up for bad grades in the past. I figured out one time that it take 8 A’s to make a single F into a moderately acceptable grade. The important thing to do is to do well in the classes now, and the upward trend will likely be noticed. If it’s a few specific bad grades, possibly re-taking those classes and doing well in them will counter the old grades. Most DO schools to this from my understanding.
I actually enjoy school, and I understand the appeal of getting another degree, but the financial expense for relatively little gain keeps me from doing it. If you’re going for a MS, then that’s one thing. You could have 5 BS degrees, and they are still just BS degrees. Others please correct me if I’m wrong.
If I were you, I would do the math on what it would cost to get another degree, figuring in the additional time, and any loss of wages during that time, and see if it makes sense. I don’t think a second degree will matter to a med school as much as good grades on some post bacc work.