How can I get past those fleas?

Hint 1 of 5:

You need to look for a weapon.

Hint 2 of 5:

It's hidden somewhere here on the face.

Hint 3 of 5:

Use the loose tooth, and you'll find the toothpick hidden in Colossus's
mouth.

Hint 4 of 5:

But before you can get rid of the big flea, you'll need to take care of
smaller ones.