White patch on lips. Due to biting?

Thanks for the query. This could be related to a skin disease called Vitiligo. It is easily diagnosed by a dermatologist and if needed a blue light (Wood's lamp) examination is used to understand it better. Kindly consult a skin specialist. Other skin conditions and close mimickers can rarely confuse a diagnosis of Vitiligo. Vitiligo has excellent treatment options and can be cured provided the patient sticks to the recommendations. There are basically 2 components of therapy – First is to stop the spread of the disease and second is to refill colour. There are different ways of doing that and it differs from patient to patient. Vitiligo is associated with other auto-immune diseases and a screening for them is advisable.

Vitiligo has to be ruled out.