Chemical burn to my lip. How long until it's better? (Photo)

I had Zoom whitening done yesterday. All the normal precautions were taken to cover my gums, etc. However, something went wrong and I ended up with a chemical burn to my upper lip. It is swollen and hurts a bit, but mostly it's just uncomfortable. Eating is hard as well. I'm unable to take Benadryl as I'm breastfeeding my baby and that messes with my milk supply. Any idea how long this will last and if there is anything I can do to promote healing? It's bad enough that I don't want to go out.