I used to lead trips in Baja California- lots of sharp spiny plants- lots of holes in thermarests, and we used ripstop tape over the hole, the a little blob of aquaseal over the entire patch to keep the edges from rolling up and to really bombproof it. if its really tiny, pinhole, then you can usually go with just the aquaseal. (look for aquaseal as a general sealant in the repair section of outdoor stores)