Dry jelq question

Hello. I have a question about the dry jelqs.
I noticed that the vein that runs on the surface of my penis (I think it is called the superficial dorsal vein) that begins from the pubic bone is getting bigger after I do some dry jelqs. Now I also noticed that there is starting to be pain in the vein and it looks really big( if I look from the side on my penis it looks like the vein is out of the shaft little scary)
I wonder if it is known that the dry jelqs are dangerous for the veins?
Maybe the grip is trapping the blood and not allowing it to move forward.
Any thoughts about this?

Thank you