Basically the title, you need to use the skills you have now and be a productive member of society.
I don’t mean go back and show the wheel or try invent germ theory etc.
For example I’m a mechanic i think I could go back to the late 1800s and still fix and repair engines and steam engines.
Maybe even take that knowledge further back and work on the first industrial machines in the late 1700s but that’s about it.
I’m a physician - am MD. As long as I don’t get burnt at the stake for witchcraft, I could go back as far as I wanted. People’s biology hasn’t changed much since Neolithic times.
Be a shame you can’t make medicines though
Just washing one’s hands before touching the patient would make a massive difference, alcohol is pretty abundant, willow bark tea for the pain (and contact your local herbalist for other remedies), you could infect people with cowpox to vaccinate them against smallpox, you might even be able to grow some penicillin if you manage to make some rudimentary Petri dishes out of broth or beer wort and happen to have the right spores floating around…
No medicine, no hospitals, no diagnostic or treatment tools? No trauma care. How much can you really do?
As a non-medical person, I can’t do much more than sterilize a wound and apply a bandage. All respect to you but that far back would you be able to do any more?
Being able to set a bone, sterilize a wound, and stitch it closed would make a huge difference for a lot of people. High proof alcohol and cauterization, and fine enough needles are the hardest parts on that list.