often you can go through a vein and further into the muscle and not draw blood out, but if you pull the needle out you can end up with some entering bloodstream.

if its instant and long lasting, did you aspirate to check for blood ??

I've had the same thing happen a few times. Also had with it a burning sensation in my scalp, fingertips, and even my eyelids of all places. I firmly believe you just passed through a vein close to the skin surface on the way in where aspirating would show no blood.

I rarely get the cough from glutes. just saying.

When you hit a vein and put oil into your blood stream, you will cause micro embolisms when the oil hits your lungs. This causes the cough. It's your body's way of expelling the substance. Higher milligram substances, especially tren, will be more caustic and cause more pain and cough.

The only thing I can think of is you nicked a vein. Anytime you get a little oil in your blood stream your body's not gonna like it. It's not just tren that causes the cough

Need stats bro