Dream about injecting someone is an indication for personal development. You need to look beyond the superficial and find the truth about yourself and about others. You are afraid of your own desires and fantasies. It expresses the beginning of new changes in your life. Perhaps you are unsure about a decision you are making.
Injecting someone dream points to a challenge that will test your character and ability. You are looking out for your own self and your own needs. You are headed on the wrong path. This is a metaphor for your passive aggressive nature. Perhaps you are pretending to be someone that you are not in order to fit in.
If you dreamt about injecting someone:
You are faced with a difficult decision. Now is not the time to back away from the limelight. Realize that the choice you make today may alienate someone else. This is fine. Do what is best for you instead of doing what is best for someone else.