Can hyperpigmentation on upper lip be treated in between laser hair removal?

Lasers can make this worse. Hydroquinone should be prescribed to decrease the chances of this. Chemical peels and Retin A are also helpful for melasma. Refractory melasma can be lasered but it can make things worse as well.

Depending on the type of laser used for your hair removal treatment, you may see an eventual lightening of the facial pigment.  Laser hair removal devices target pigment in the hair follicle.  If there are cells at the same level as the hair follicle which contain dark pigment, the laser will affect them as well.  In some cases, the cells may be stimulated and make more pigment, in others, the cells may be destroyed along with the hair follicle, and over time (2-5 days), the pigment released from the damaged cells will rise to the surface of the skin and flake off.  It may look darker initially as the pigment is no longer contained inside a viable cell.

Pigment can be treated with other modalities between hair removal treatments as long as the pigment treatment is held for at least a week before the next scheduled hair removal to minimize the risk of skin damage by the laser.