IM Injection gone wrong

[csharpprogrammer]

SWIM attempted his first ever IM injection today with 5 mg midazolam. He prepared the arm with an alcohol prep pad, then pushed the needle forceful into his upper arm, where his doctor usually gives immunizations. He thought he had pushed hard enough, only to find that the needle barely broke the skin. SWIM proceeded to push the needle, which was still stuck in his skin, slowly and he felt the needle break what he assumes to be a layer of fat. Getting scared, and not wanting to go any further, SWIM was going to push the 1mL solution into his arm, but all of a sudden SWIM felt a "pop" so he immediately pulled the needle out without injecting the midazolam. As soon as he got the needle out of his skin, blood poured like when a nurse removes an IV catheter. SWIM acted quickly with a cotton ball and added pressure. He then taped a cotton ball over the wound. SWIM's arm is no longer bleeding, but he is wondering what went wrong??? Could some SWIY please provide some instruction on giving IM injections.