Hello and welcome to healthcaremagic
I think you are concerned about
tanning. UV A part of the electromagnetic spectrum is mainly responsible for tanning
I would suggest that you use a broad spectrum sunscreen, that which offers both UV A as well as UV B protection throughout the day.
It is important to select the right sunscreen for desired effects. A sunscreen with minimum 30 SPF would be adequate. It should mention both UV B and UV A coverage.
It should be applied in the following quantity:
--3ml for face and neck(a little more than 1/2 teaspoon)
--3ml for each arm(a little more than 1/2 teaspoon).
A sunscreen should be applied every 2-3 hours.
At night, you could use a skin lightening cream containing one or more of the following ingredients like
kojic acid,
glycolic acid, arbutin,
magnesium ascorbyl phosphate,
liquorice etc to gradually fade away the tan.
regards