As i understand it you may legally bring back across the border from Mexico a three month supply of medication for personal use if you have a valid prescription obtained in Mexico. The medicine must be unopened as well i believe and you must declare it at the border, sign a little Customs form.
Recently a new law was passed that allows you to bring back 50 units of a drug without having a prescription.
The only problem with all this being that while it is legal from a federal standpoint, the state of Texas can and will pop you for possession if they caught you. It is supposedly rare but does happen.
Am i right or wrong?