800mg in 2ml is to much at one time for 90% of guys. i'm going to suggest split that in to two times per week

to me it sounds like you hit a vessel or nerve which can swell up and hurt pretty bad. throw in high mg in low volume pip and you got a winner.

-make sure to stay out of that glute for 4-6 weeks
-always aspirate
-if uncomfortable pull out and change needle tip and move over one inch (i just did this yesterday)

infection is last resort as by default gear when made right/normal, has chems in it that kill all the bacteria and continue to set in the chems. of course made with high heat and filtering process and all that even further the case. and one can assume your doing everything right on your end. however a user can still make the slightest unnoticeable mistake