kbars, failure once in a while is common and expected, even. The drug may have been injected in tissue outside the cavernous cavity, the drug may have raun back out of the penis before being adsorbed, and any number of other reasons. One failure isn't anything to worry about
. Do you use the preplump method of getting some blood into the penis to enlarge it somewhat, then injecting and holding the blood./drug mixture in the penis for a couple minutes by clamping with the fingers or using a penis ring? That sems to work for those who experience failure often. Wait a couple days and try again.