Fixing a flat...need help!

Ok, making my first attempt at changing a bike tire solo.  Thankfully I had enough air to get me home so now I can take my time and get some practice.  So here's the question.  I apparently ran over some thorns on my mountain bike.  Lots of thorns.  I pulled more than 10 out of the back tire.  I got all the big ones but there are still some little spots in there that look like they could be thorns but it's hard to tell.  They're down in the grooves of the tire and too deep to pull out w/a fingernail.  So what do I do about these?  I'm not even entirely sure they're thorns, but I don't like the idea of putting a new tube in when there may still be sharp stuff buried in there somewhere.  Help!!!