Roof of mouth problems?

i have a hole in the tissue of the roof of my mouth.. i dont have a cleft palate or anything b/c its new. it just showed up a few days ago & people told my it was a canker sore, but i dont think you get those on the roof of your mouth.. anyway, i swished w/ saltwater like you do w/ mouth ulcers but the hole seems to have gotten longer. i'm going to the dentist on monday, but i'm wondering if i shuld be worried... it doesn't hurt too much, but i have no clue what it could be.