Had A Small Moll

I have had a generally small moll/freckle on my left breast next to my nipple ever since i remember. now that i m fifteen, it seems like the mole is stretched out looking and has gotten a light brown area spreading out around the light brown center on the mole. i go in tanning beds sometimes and i don t usually wear sunscreen. i m afraid this is skin cancer but every time i m in the sun or a tanning bed this area is covered by a bathing suit ? i also thought that this could have happened because my breasts have significantly grown since i was a child obviously. please help ?