My 25 yr old grandson had the same thing happen suddenly - and nothing helped to bring down the swelling. Lips chapped so badly that he could hardly speak or smile without excruciating pain.
We finally stopped the swelling by using DMSO. Go online and do your research on this. Used heavily by doctors for athletes to immediately take away swelling. The FDA won't approve it (although it has a Very long list of cures, with the only side effect for a few people, being a slight garlic taste). The main reason seems to be that it is so cheap, the drug companies and some of their high priced prescriptions would lose billions of dollars.
It's a clear liquid (made from trees) which is applied topically. You must be sure that you either have clean hands - or use a Q-tip - to apply it.
Also make certain that you get the pharmaceutical grade. We got ours from a site called dmso.com - and a pint will last for years since it goes a loooooong way. The FDA requires that it be labeled as a "solvent" and not for medical purposes. Repeat - go online and do your research and make up your own mind.