If it is vapers tongue, that can be a real beast.
I've had it 3 times now.
First time was about 3 weeks into vaping.
I didn't know what was going on. Thought my hardware was wearing out.
All my flavors tasted weak. About 20% of normal.
It passed after a few days.
Second time was a couple months after that.
I literally couldn't taste anything. That time, I had been vaping the same juice for over a week.
It was a strong juice.
I tried mouthwash, excessive brushing, tongue scraping etc.
It was so bad, I was chewing on lemon slices. They tasted like air.
I made a batch of unflavored juice and vaped that for a couple days, all the while drinking lots of water.
After it passed, my juice tasted better than it ever had before!
The last time around, was just last week.
I noticed my juice tasting a little weak. I knew what was going on.
I had been vaping the same flavor for several days.
It is a peppermint/chocolate flavor. It was weird because all of a sudden, I could no longer taste the chocolate, but the peppermint tasted fine.
I started drinking lots of water and switched away from that flavor.
I vaped very light flavors and even some unflavored.
It lingered for a few days and seemed to get better, but my favorite flavor still tasted a little weak.
It's been about 7 days, and all is back to normal.