Weird tooth thing

[morethanacondiment]

6yo DS is making slow progress with his adult teeth. He's lost the bottom front right, and the bottom front left is growing up behind (he loves his shark tooth!).
He told me today he had a new tooth growing...tricky to photograph, but it looks and feels like a new tooth is growing up in front of his adult bottom right tooth.
It feels sharp like a new tooth, but difficult to see much.
Is it likely to just be some kind of ulcer? Broken thing? Or is it worth a trip to the dentist?

Difficult to see clearly in photo, but it appears to be an ulcer. Possibly a traumatic one.
Is the retained Lower left primary central incisor loose at all? If so, encourage your DC to wobble it out ASAP. A very good chance then, that the tongue will push the newly erupted permanent incisor forward -into a better position. Get nagging!!-you've got a window period .

It looks like one of his left adult teeth (right side of middle as you look at the picture) is growing up behind his baby tooth there and the equivalent right side has lost the baby tooth and has the adult tooth in the correct place. Ideally get him to wobble the baby tooth out and the adult tooth will probably move into place. DD3 had something similar a few weeks ago and the adult tooth has sorted itself out quite quickly into the correct place.

Yes, adult bottom right grew behind too and naturally moved forwards when the milk tooth fell out. It's just that the thing at the very front (on the right, so in front of that new tooth) feels like a tooth because it's hard and sharp! Good to hear that it could be an ulcer though - well, not good, but you know what I mean!
Thanks both.