dull needle (question)

[Dutch Tank]

Some time ago I was going to inject a friend of mine..

He only had one needle and had 2vials with a little test in both.. So I drew up from the first vial, trying to suck all of it out bumping into the sides and bottom of the vial.. Then same story for the second vial.. Then I had to inject my friend..

I said: this may just hurt a little.. I put the needle to the skin and tried to penetrate the skin.. The skin denced in about 2cm (almost 1inch) and then it went in... He had pain for 3days..

Lesson: Alway make sure you have enough needles haha..

Sorry for the bit off topic..

On topic: Yeah just keep the "old" needle on so nothing can get into the syringe or come in contact with the substance...