Pigmentation around mouth is usually due to b complex
vitamin deficiency. Sunlight does not play a role in causing it. I suggest you continue with your
b12 injections but also take some multi vitamin tablets including vitamin c to help in improving the pigmentation.
Take some early morning sunlight to improve your
vitamin d levels.
You are welcome to contact me at Juvenis Clinic for further advise.
Dr Nilesh Goyal