Probably spiderwebbing... a sealer & glaze product such as step 2 of the Mothers 3-step Ultimate Wax System will help. Check out the Prep, Seal & Waxing section of the Detail Guide and see if you think it'll help -- I bet it will.

There are lots of other similar products out there, but that's one good brand to start with and it's quite easy to use.

The other option is just to now look at your car under fluorescent lights... they show everything!