My daughter is 4 months old and teething, her pediatrician said she probably won't break her tooth through until she is about 6 months. Lately she has been biting down on my nipple, it doesn't hurt just stings. By the end of the day though my nipple hurts bad from her biting down. I tell her not to bite down or I will take her off and she looks at me and smiles. When she does bite down after I warned her I end the feeding session, mainly because I am sore and need a break. What can I do about this? I know she's pretty young and doesn't know any better. Do I just deal with it?