7 month old cracked lip

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My 7 mo has this crack in his lip and he’s had it for a few days now and he woke up from his nap and I noticed it’s bleeding a little.

I’m not sure where it came from and I’m also not sure what I should do about it? I noticed he sucks on his bottom lip a lot and he’s got one tooth but it’s on the other side of the crack. Any help would be appreciated