Mandala/geo tattoos aren't my style, but I think it looks fine, looks like a tattoo and gives the "sleeve" look which some people desire.
I try to resist the urge to get extra tattoos at the end of a session. Especially to just fill space for the sake of filling it. You're endorphins are going and it can make for clouded, hasty judgement and second-guessing. I know cause I've done it before. Stick to the initial plan and if you still have gas in the tank, I'd save it for the healing. Then you get to have an extra visit and hangout at the shop for the next tattoo. My $0.02