White spots after whitening strips - will they go away?

The appearance of white patches can be troubling when you are actually trying to improve the appearance of your teeth. 
Though you may find it hard to believe, the white patches were already on your teeth, only they were not as white, as they were stained the same way your teeth are. The patches are wrongly-mineralised areas of tooth tissue. Being wrongly-mineralised also makes them more porous, and the difference between them and surrounding tooth and lets them catch the light and stand out. 
As they are more porous (read absorbent) they race quicker to whitening gel. 
When you whiten your teeth the dehydrating effect of the whitening gel during the course of treatment also makes the white patches look whiter than they are.
Do not worry though, with enough whitening your teeth will catch up with the white patches, and so blend in better with each other. If there is still a difference you can use treatments such as Icon to improve the appearance. 
So good luck with the whitening and things will look better -

Thomas Dey BDS, MSc

Hi:The white spots should be temporary.  They normally last 24-48 hours. It's best to wait for the white spots to go away before doing further treatment.Best,Dr. Maddahi