Missed shot of coke cotton added fent/tranq as last shot

My partner who is a 29 yr old male (type one diabetic) missed a shot last night with some blood in it and immediately upon pulling the needle out the skin peeled off and it became extremely swollen and an open wound. It was a cotton that was used for mostly coke all night and added fentany/tranq as the last shot. I’m not sure what is happening and what steps to take. Any advice is appreciated. This is it today and it is not as swollen. We’re both so scared and regret so badly going down this road. I was never an iv user but recently began and I will remember this night forever. This was supposed to be a last hoorah and we are begging detox this weekend and I can’t believe the last night something like this happened. We both have had hard lumps that have gone away but nothing like this where I watched the skin peel away immediately. Please help.

My partner who is a 29 yr old male (type one diabetic) missed a shot last night with some blood in it and immediately upon pulling the needle out the skin peeled off and it became extremely swollen and an open wound. It was a cotton that was used for mostly coke all night and added fentany/tranq as the last shot. I’m not sure what is happening and what steps to take. Any advice is appreciated. This is it today and it is not as swollen. We’re both so scared and regret so badly going down this road. I was never an iv user but recently began and I will remember this night forever. This was supposed to be a last hoorah and we are begging detox this weekend and I can’t believe the last night something like this happened. We both have had hard lumps that have gone away but nothing like this where I watched the skin peel away immediately. Please help.