Alot of people get Hole in the Head mixed up with natural sensors. Oscars do have sensors on thier head and it is often confused with small cases of HITH. Posting a pic would help out a lot.
I agree with the above post. As on Oscar ages, the lateral lines and the sensory pits on the head become more pronounced, and are often mistaken for Hole in the Head (Head and Lateral Line Erosion)