Thermostats are suppose to "fail safe", that means if it should fail then it would stay fully open.
"Suppose to" is the word to watch out for.
Thermostats use a wax like substance in the center rod, as it heats up it melts and becomes a liquid and that allows thermostat valve to open.
Since yours seems to have been stuck open for a bit that could mean it is failing, and they can fail closed..............so overheat engine.
Keep an eye on the temp gauge and PULL OVER if it starts to climb, DO NOT try to "make it home" or any where else.
Let it cool down, then check coolant level, if it isn't a leak, then start engine and drive until it starts to climb again, then pull over and let it cool off, repeat, until you get where you need to be.
If it takes you 3 hours then you are making $200 an hour minimum, because you WILL blow head gaskets if engine gets too hot, not maybe, WILL, and that will cost you $600, if 1 head cracks add $300