Will Autoject E work with any needle ? just got 20 from my Doctor and don't want to waste them.

My first self inject was a flop. No erection and some, not much, blood around foreskin area. No pain. Called Dr he said missed the spot and since no pain don't worry about it and come in next week and we'll go over it again. OK, went back to Dr's for second self inject. All went great. I"ll rep...