Tapping out too early?

Started on my sleeve yesterday. (Wanted to do a coverup instead of working off it due to my previous piece being done when I was young. I’ve grown to hate it over the years as I got it done while struggling with addiction and have noticed all the imperfections after 6 years.) It’s going to be a full “blackout” arm sleeve done in a negative art style so white will be added eventually. I felt bad having to tap out after 9 hours before this section of black could be finished but I just couldn’t tolerate shading anymore.

My artist was ready to keep going well past our scheduled time and I felt I let him down. The white ink is supposed to be worse in terms of pain. I want him to be able to stay in the flow until he calls the session to an end. Any advice on how to better combat pain during a session? Is the pain something I’ll get acclimated to? Is it okay to end early after a session that long? He was really chill about it and I tipped well due to the inconvenience but I didn’t want to disrupt his flow for breaks every 30 minutes. Tattoo stories are also welcome as this is really my “first” tattoo getting professionally done at a shop. I had no idea what to expect and was a night/day difference from my original piece I got underneath it years ago.