How To Treat Pimple Like Bump Between Breasts?

I have a very small pimple like lump in between my breasts. I'm 14 years old. I told my mom about it and she said not to worry about it... I tried putting some acne treatment stuff on it but it's still there. I've had it for about a couple weeks/months. I don't think it's really anything, but I'm just concerned about the way it looks.