It would be better if you could post an example or show a link to the pic some where.
If the highlights are too blown out you may not be able to recover them.
If you are working on JPEG then go to IMAGE>ADJUSTMENTS>LEVELS.
With the LEVELS window open get hold of the centre slider which is the mid tone slider and move it to the right and see if it lowers the blown out whites.
Bear in mind this will lower all the mid tones so it may be an idea to duplicate the layer first and after the adjustment is made erase the parts you dont want.
There are better but more compicated ways to do this.
It may be an idea for you to search the net for tutorials on Photoshop......YouTube has some good ones.