I have gone to Mexico (also from TX) and bought meds and brought them back. As long as you only have a 90 day supply and declare them at the border you shouldn't have any problems. Worst that could happen is that they would get seized but that has never happened to me.
Also, and this may depend on where you are entering from, but there is usually a line of guys that will take you to a pharmacy or whatever you are looking for for just a few dollars. Most of the pharmacies over there have "staff" doctors that write the scripts.