Tongue ulcer

Noticed tonight my 15 month old has what looks like an ulcer on the side of his tongue. Can’t tell if it’s bothering him since he’s cutting a molar on that side. He’s had his fingers grabbing at that side for a few days but I don’t know if it’s the tooth or this sore or both. Could it be from the teething? He hasn’t had any new foods recently so I don’t think it’s an allergy. Is there anything I can do to soothe it in case it is hurting him? Should I call his doc in the morning or wait a couple days to see if it heals on its own? Just not sure how seriously I should take it because it doesn’t look that bad but it’s new for me.