what am I doing wrong?

Hello nurses! I'm wondering if anyone can help me. A friend of mine who is a 55 year old male requires testosterone and B12 injections every two weeks. Because I am a pre-nursing student, he asked if I would be willing to administer the injections, and of course, I agreed. I have now been giving him the injections for about a year. Originally, we went to his doctors office and the nurse there taught me how to administer them.
About the last 5 or 6 times on giving him the B12 (which I have injected into the thigh) the skin will raise up, creating a bump, and he bleeds quite a bit. I have pushed back the plunger every time to make sure that I have not hit a blood vessel. When I administer the testosterone in the buttocks, there are absolutely no problems. I even gave the B12 in the buttocks once and the result was the same, bleeding, with bump. He says that he is just happy to have someone that will give him his shots for free but I feel terrible every time that I have made him bleed and sent him home with a knot . Any ideas how I can fix this? Thanks for your time and any replies.
I would try alternating sites. If you havent tried the other leg, maybe try the deltoid, depending on the dosage. I have given B-12 injections in the deltoid and it went fine, as long as its not a huge dose. There is a limit to what you can inject in the deltoid, I beleive its 1ml. Hopefully that helps.

What size needle are you using and how much of the needle goes in when you give the injection? I could be wrong but it sounds like maybe you are not going deep enough, so the medicine is under the skin rather than in the muscle.

if i'm just paranoid hopefully others will write in but i'd be concerned that you would be liable if something happened such as anaphylaxis or skin necrosis resulting in sepsis etc. i know it would be rare but with my luck bingo. i wouldn't chance anything that might result in not getting licensed or jeopardize my nursing license. i won't do anything for anyone that isn't my patient with the exception of immediate family members. i don't even take fellow employees blood pressure, they can work the machine themselves and decide what to do with the data.

i have usually given in the deltoid also

Quote from jules aif i'm just paranoid hopefully others will write in but i'd be concerned that you would be liable if something happened such as anaphylaxis or skin necrosis resulting in sepsis etc. i know it would be rare but with my luck bingo. i wouldn't chance anything that might result in not getting licensed or jeopardize my nursing license. i won't do anything for anyone that isn't my patient with the exception of immediate family members. i don't even take fellow employees blood pressure, they can work the machine themselves and decide what to do with the data.

Go back to the hospital, show it and ask if you are concerned. What can we do here without knowing what is going on?Another issue. I don't know this for sure first of all. Since the nurse taught you how to do this injection, I am assuming it would be something where family or patient self can administer it at home, just like insulin subcut injections. In this case, a friend is administering per patient request. Or maybe the nurse was just talking through it, hoping the patient will be back with the nurse to get routine administration. I wonder this; did they say it is okay to administer it at home by you?