You can use abreva I am sure it's a topical cream I'd call the dr and ask them if they say yes def abreva if not you can try a warm rag and putting tooth paste on it while sleeping my mom gets them bad and so do I my whole lip swells sometimes good luck
Treating things during pregnancy can be very tricky. You should call your doctor and see what they recommend. Otherwise, you may have to let it run its course.