Ha! Finally one! 
True, especially since it’s not red or hot - but if he starts to open it himself, he might very well get an infection. Especially considering that…
… is far from being sterile or even sanitized. Honestly, I’m pretty surprised that any artist would give an advice like that.
With my silicone implant, there was a swelling (guess it was fluid buildup) for some time, too, and my artist considered a drainage as well - but he would have ordered me to come over to his studio (2 hrs. train drive, one way) or have it done at my local piercing studio (he knows my piercer personally and trusts him enough for that). He would never have told me to open it up myself.