Your elbows are seriously f****. There are several factors. Work on all of them:
-Take a total break from that exercise, or it necessary from all exercises, until the pain goes away. Then:
-Do a compound exercise for tris before this exercise, to warm up the elbows. Then do a couple of lighter warmup sets of this exercise.
-Keep the reps moderate, no lower than 8 for this exercise. If the pain persists, stay around 10 reps/set or higher.
-Rest between sets of no more than a minute.
-What is the ROM on this exercise, where are you lowering the weight? Describe the motion you're using. The form you're using, or the exercise itself, may have to be eliminated otherwise the pain could return over and over again.