Welcome. I'm new here as well and I'm amazed at the abundance of information available in this forum.
I'm no expert on hppd and didn't even realize it had a name until recently. You're still having visual issues like visual snow and colors, is that correct? Are they present all the time?
I understand that psychedelics can teach us many things. However, there are some of us, like me, who end up with symptoms that we experience every waking moment. When I started using psychedelics over 40 years ago I thought they were some sort of miracle and shaped the way I experience existence in positive ways. However, I see visual patterns almost all of the time and have for decades. I dosed heavily for about six years.
I'm not a doctor so I won't dispense any medical advice. The advice I would give is to stay sober for a while to see if the symptoms go away. If they don't please understand it might get much worse if you continue using.
Also, if you do have hppd, don't panic! Even if you have this condition, it's possible to have a wonderful and productive life.
I hope your surgery to remove your cyst goes well.