Got a tick in the back of my arm with a head left. Wyatt coudn't get it out - now I have a hole in my skin and a part of a tick still there..
Would you recommed to leave it or have a doctor to remove it tomorrow?
I would definitely see the doctor immediately.
I absolutely second Mike. Don't take a chance with Lyme
I hoped to see this when I checked in here.

If you got most of it out, you won't get Lyme from the leftover head, but they do tend to rot which is pretty unpleasant and itchy. when I have part of a tick in a hole, I wouldn't leave it or wait for tomorrow: I'd keep digging/tweezing until its out (or get jane to do it). A big hole with no tickhead will heal faster than a little hole with a tickhead.
(This has happened literally hundreds of times).
And, watch out for the Lyme rash, obvs.
If that’s not enough, even if you get it out it will likely take a while to heal.