Possibly a dermatologist if it is a skin condition affecting the lips. If it is an infectious disease you are concerned about, then a doctor in the Infectious Diseases and tropical medicine department may be most appropriate. If you go to see your general practitioner or to a walk in centre, they should be able to point you in the best direction.
Dermatologist treats that condition
The Dermatologist (skin doctor)
Foot doctor
I think its an orthapeadic doctor
an oncologist
nuerologist
gastroenteroligist
A psychologist.
A gastroenterologist treats stomach pain.
A GP should do.
animal doc.
podiatrist