Here's a pic of the coleus

good grief! I didn't know anything ate poinsettias. They have that toxic sap which most things seem to avoid. Look around for slugs/snails and if that isn't it I'm at a loss.

> I didn't know anything ate poinsettias.

Huge enormous hornworms adore poinsettias.

Looks like caterpillars of some sort - they can be small & sneaky & hide themselves very well, since many will be the color of the leaves they've ingested.

I scout the undersides of leaves to find the critters & squish them, once found. Some might hide @ the base of the plant.

Or you might try a Bt spray - it can take a few days to work - once used, check for fresh damage (fresh cut edges, not dry &/or corky) to verify.

HTH