I have used GTP T400 before. Real good stuff, but it is really, really brutal. Doesn't matter if you heat it up, massage, etc. IT HURTS. Never shot anywhere but my glutes, too scared after I saw how they reacted. Wife was so freaked out, she wanted me to go to the hospital when she saw it. I was doing a shot every 4 or 5 days, I don't remember now, but I remember that each time I took a shot, the cheek had just gotten back to normal. Took 4-5 days for the burning to go away, about a week for the swelling and redness, and up to ten days or so for the knot to completey go away. B-)