I’ve had it a couple of times. The problem is inflammation so do things that help with inflammation. NSAIDs (ibuprofen etc) are good. Hot baths are not.
The main thing for me was ice. Ice in the morning, ice in the evening, ice whenever you get half a chance.
Also taping helped, you use athletic tape and tape up your foot/heel such that as you walk the tape takes the tension that your plantar fascia otherwise would. Lots of guides on the net.
I also tried the calf/ankle splint things that hold your ankle flexed while you sleep. These I found just woke me up in the middle of the night with chronic aches in my ankles/calves. YMMV.
Best of luck with it, mine was making me pretty miserable after a while.