Can martial arts tighten loose skin?

I had gastric byp surgery last year and lost 165 pounds in 10 months...unfortunately that left me with quite a bit of loose abdominal and thigh skin. I am enrolling in a tae-kwon-do cl and wonder if it can tighten those areas, at least to where they are not as visible. It is not horribly bad, but it makes me self concious, espescially around my boyfriend.