A Few Times A Year I Have Been Getting Tiny

A few times a year i have been getting tiny dry bumps on my lips. No amount of lip balm helps. I have only had one partner during this time. He has been checked and he is clean for everything. It's not itchy and they don't seem to be sores because nothing comes out of them and they don't turn into anything other than the tiny bumps they are. It just feels like having EXCESSIVE dry lips. But it is very irritating and it last for a few weeks. Help!