When a baby is latched correctly, he is not able to bite, because his tongue is over his bottom gum (and teeth). It is when babies are not actively feeding that they may bite. This is usually at the beginning of the feed or at the end.
If your baby is teething they may go through a biting stage. Try giving them something hard and cold to chew on prior to feeding.
Newly erupted teeth can cause indentations and can be quite painful. Make sure you have the latch correct to prevent pain.
If you do get bitten, treat this in the same way you would a sore nipple. Breastmilk works well as well as the nipple balm. See your LMC/ GP if these measures do not promote healing, or if the area becomes inflamed or infected.
Some babies bite because the milk does not come quickly enough, or at the end of a feed when they have had enough and are playing at the breast.
If your baby tends to bite because he is impatient, it may help to express a little before the feed so that the milk flows straight away. This might only be necessary when your baby is tired or very hungry.
If he does bite, saying 'No!' firmly and taking him off the breast straight away will teach him not to do it. Try to avoid a loud 'Ouch!' as this may either frighten your baby, or alternatively amuse him, so he may try it again.
Some babies seem to experience more discomfort than others when teething and sore gums may lead to refusal to breastfeed. Discussing suitable pain relief with your GP and offering your expressed breastmilk (eg in a cup) may help.
Sometimes, a baby who has been frightened by his mother's reaction to being bitten, refuses to go on the breast.
Finally, biting, if it does occur, is nearly always just a temporary phase. If you are still having issues feel free to contact me