A good venipuncture return but bulging is a failed puncture. The procedure should be repeated. Remove the needle from the failed venipuncture and apply pressure for a few moments. Re-select a better and straighter vessel, then select a good angle of entry, disinfect the skin, tense the local skin so that the vessel protrudes as well, the angle of entry is small and can be kept less than 20 degrees, pierce the skin and pierce the vessel, after seeing the return blood, follow the direction of the vessel and then advance a little bit, then enter the needle in parallel and do a good job of fixing the piercing needle handle.