First time this has happened to me.. I gave myself a shot in the quad and right when i pulled out a lump(hard knot) started to form. What does this mean? Needle hurt a bit more then usual when i was putting it in.
You injected next to a small vein. The oil pressure from the injection caused it burst. It'll get hard, it may become incredibly painful, and then it just goes away.
99% of the knot went away.. forgot about it all day, then i looked at it and about the size of a quarter is all red.. Guessing i did pop a vein. Still no pain though