Well, if you have any skin problem that is NOT "just cosmetic" - such as acne - a dermatologist might, if he wants to, remove the mole at the same time he is treating your acne.
Aside from that, you know, kids will pick on you for ANYTHING. It's not the mole. If you didn't have the mole, they would have chosen something else. It's a teen thing - ALL teens feel ugly. Some of them think that by putting others down, they will lift themselves up. Some people don't grow out of this, but most do to some extent.