It may looks like HITH in cichlids, but actually it's caused by fungus. Different diseases, but same cause - dirty water. Weekly water change, and vaccuum the gravels/substrate will help.
This is not a recent problem. I've always seen these holes on my jar's head. The other side has only 1-2 small holes. I've seen these holes/marks on other jar's too.
I only have a very thin layer of gravel in my tank, just enough cover the bottom.
yeah, that is HITH, that's how my jardini looked like a couple of months ago. What I did was cleaned the water every other day and it went a way. The holes were deeper. You should be able to treat it but it will take some time.