OK, I'm 15 years old, slim, and I shower everyday and use anti-perspirant.?

Since you are only 15 you will probably outgrow it after a while. However, in the meantime there is an anti-perspirant called Certain Dri. I included a link at the bottom so you can see what it looks like. You can buy it in most drug stores. It costs a bit more but it really works. You put it on at night and sleep with it on. (I used to use a spray in the morning as well) This stuff totally works. Just don't put too much on because it can irritate your skin. ( Also, it used to itch like crazy at first if you put too much on.) It will take about a week of consistant use to see a difference. Eventually you will want to use it every other day and then less and less. In between you will probably want to use Dove with moisturizers because it really dries things up. Eventually, you won't have the problem at all. It worked for me and my sis. Also, people used to tell me to use Mitchem but it never worked for me and it was yucky sticky! Scroll down on the link and you can read bunches of testamonials for the product. This really works.