dude....i work as a vet tech and have access to quality inj b com and b 12... did b12 1 ml once a week indef. started in my thighs IM.... winded up doing SQ in my stomach and experienced the same thing you are... do it IM and massage....5ml's anywhere is toooo much in my opinion. 3ml max. massage and heat. b 12 aint that great unless u really need or have been prescribed it.