I used my older apple watch charger on a trip. Since then my apple watch 8 does not charge reliably when I use my usb c charger. Is there a fix?

It is extremely unlikely your use of a different charger has caused a problem. The unreliable charging is an annoying coincidence. Both the older USB charger and the new USB-C charger are compatible, and they should be interchangeable in practical use, the only difference is that the USB-C charger can perform high speed charging. If you are seeing poor performance from the USB-C charger it is likely to be a hardware problem (damage?) with the charging accessories.

Inspect your charging hardware carefully, and be alert for any damage on the cable between the power adapter and the magnetic puck (also use your fingers and *feel* for any irregularity in the cable). If you have more than one power adapter then test by substitution. Also I suggest you try a different AC poser socket just in case there is a problem.

Try this:

1. Press and hold the Digital Crown and Side button at the same time.
2. Hold until the screen goes dark and the Apple logo appears.

Then wait and see if the home screen/face appears