Baby canker sore

Kayla • 04.23.16 👦🏼💙 12.26.18 👶🏼💗
My one year old has a canker sore on the inside of his lip. Could this have been caused by him biting his lip? (his 1st 2 teeth are coming through). It wasn't there this morning but was when I picked him up from daycare. Is it something to be concerned about?