VCs_TL

i am going to take my car in concerning an imperfection on the trunk. there's a spot, about the size of a nickel, where the it looks like there's slight bird crap on it. but when you go to touch it, it's smooth. i wash my car pretty often and zaino it 4-5 times a year and i notice it getting bigger. has anyone have this problem and what can/will the dealer do about?