on lower lip may be leucoderma
following inflammation due to relapsing herpes labialis. It is a mild viral infection caused by HSV virus.
You may be having relapsing mild herpetic lesions on lower lip,which may be responsible for white spots on lower lip.
400 mg daily for long time. Immunobusters like levamisole
50 mg for long time. Apply acyclovir cream,when you feel redness on lip. When there is white spot, you apply tacrolimus oint. You may be improved.
Do not apply cosmetics or lipsticks on lip. And do not prick or squeez the lip.
I hope you got my answer.
Dr. Ilyas Patel MD