Follow-Up:
For my enitre life my lower lip, but strangely not my upper lip, has spontaneously covered itself with scabs, which are most often thin, clear, and smooth, but sometimes rough and brown, and they eventually flake off, after which they are quickly replaced with new scabs. I haven't bothered to measure the time parameters of the scab cycle, but it is roughly the same as that of ordinary injury-provoked scabs. I do not have burning in my lips, mouth, or otherwise. Topical balms and supplements of all kinds are ineffective. The only other symptoms that I have, which might be related, are small itching swellings that occur deep inside the lower lip on occasion (about once every 3 months, I estimate), and small non-itching swellings that occur in my lower nose, near the mouth, about equally as often. The symptom of the swellings sounds like it is caused by a virus that is similar to herpes, whereas the scab formation sounds like it is caused by a genetic mutation that causes an overactivity of the scab-forming proteins in the lower lip.