As for your camera, is it a compact or an SLR-model? In either case, don't use any paper-towels or other cloth at first...
Simply use some compressed air from a can and see if you can blow it all off.
Be careful, start with the air from far away or the force would cause the small sand/dust-parts to scratch on the lens.
Check and if there's any particles left, try to move the air a bit closer and more direct at those spots.
If it doesn't help, off to Mr.Camera and let him open it up, clean it...
Good luck with it...
Luc