What causes swollen lips after making out?

Blood flow: Kissing will increase the blood flow and this can cause some swelling. Sucking and biting will cause some swelling and this will go away. The one cause for concern is allergies. It you have allergies to, the foods that your partner ate recently you can be exposed and can have a allergic reaction.

HSV1: Herpes simplex is highly contagious and can easily be transferred by the exchange of a lip kissing.The good news is that HSV1 often clear without any treatment.

Hard to tell: You could have sensitivity to whatever he has on his lips or could have accidental bumps in the heat of the moment and the it could be an infection