I still have no idea what you guys are saying
I think what they're trying to say is that sonic's muzzle should be wider, like this:
those sprites are looking good.keep the good work!
Oh, I see. The problem was that I think I did a circle for the head and it had the correct size, but I had to enlarge its eyes to the other side, making a non-perfect circle for the head, making the muzzle look smaller than it would actually be. But now you enlarged the muzzle too much. Sonic's head is a perfect circle, no bumps other than his nose, ears and spikes basically (his eyebrows in japanese classic Sonic artwork is way too thin and small to actually be considered)
Anyway, I fixed it: