What does a baby's first tooth look like when it is coming in?

My son has been aggressively chewing his fists for weeks, has lots of clear, watery drool and has been cranky today. Could he be teething? He has a little white dot in the very front of his bottom gum line but I can't tell if it is on top of his gum, under it or what. I can't feel it at all but he seems to enjoy it when we rub his gums. He is only 3 months old though.