Swollen Upper Lip - Zoom Whitening Side Effect?

It is possible that the heat from the ZOOM lamp caused the equivalent of a sunburn on your upper lip.  The likelihood of it being an allergic reaction to the whitening gel is nearly impossible, since whitening gels are peroxides and the human body itself manufacturers peroxides on a daily basis (sometimes, 10x more than the amount of peroxides in whitening gels).  If your clinician placed a latex barrier over your lips, perhaps it is an allergic reaction to latex.  This can be easily verified by a dermatologist.

In the meantime, using cool Aloe Vera is your best option if it is indeed a burn.  Ibuprofen (Advil, Motrin) will help with discomfort, and Arnica can help decrease bruising that could result from excessive swelling.  You should see improvement within a day or two. 

There are RARE unusual reactions to all medical procedures and medications. The human body is still 90 % a mystery.  You might ask your dentist about prescribing Medrol Dose Pack if the swelling is significant.