Kingcarb-

The stretch marks are from being overweight, not losing it. Your skin stretches and shrinks as your body grows. When you pig out on food all the time, you body gets fatter. Good thing we don't just pop out overnight or our skin would pop too. Anyhow.. same thing goes for losing weight. When you lose too fast, be it by some miracle drug or liposuction, you skin doesnt really have time to stretch back. So it does what it can. Its just going to take time to firm back up to normal.

You can do abdominal exercises to help "take up the slack". Just use resistance when doing the exercise. This will make your abs grow. Also, drink lots of water. I would consult a doctor or do some research online about people that have plastic surgery and what they do to recover. I wouldnt even consider a "tummy tuck" unless it was the very last option and I'd been that way for months.

You're young. Have patience.

Good luck.