Had burning feeling in tongue over decade, but some five years ago i noticed circular shapes forming on my tongue. They are not always there but sometime they appear, never one, sometimes smaller sometimes they go big. They are anywhere on tongue, but mostly dorsal or sides. The ones that appear on tongue tip can cause burning feeling for some time. They appear very suddenly: first there is burning feeling, then after some hours patch appears; then within hours the patch widens, the center is clearing and it appears as a circle with fading white border. At this point burning feeling is gone. Sometimes they stay week, sometimes they clear withing days.
Some pics, one is made recently, one year ago: