baby biting

Robin

My little guy is using those sharp little teeth of his to bite mommy. I'm the only one he bites, and he is biting hard enough to leave bruises...he's even started breaking skin. I tried hot sauce, he likes it. tried biting him back but he laughed at me. I can't spank him, he's just a baby (18 months). And he doesn't care about time out. I'm at my wits end, what else can I do?