Pineapple burn, lol

The strangest thing happened to me last night. I bought a whole pineapple 4 days ago. Yesterday morning i juiced half of it, and put the other half in the fridge, so i can eat it in the evening. The juice didn't give me any problems. Then i ate the other half in the evening. When i finished eating it all, i could feel a little tingling on the right side of my tongue (i did most of the chewing on the right side). I went to check in the mirror, and there was a huge hole in my tongue, lol. I'm serious! It looked just like someone burned a hole in my tongue with a cigarette. And i do mean hole, it was pretty deep. This happened yesterday, and i can still see it right now (but the pain is gone). i heard acidic fruits are bad for tooth enamel, and i always rinse my mouth with water after eating them. But i never thought this would happen. It was pretty ripe when i ate it, because i bought it 4 days ago. Maybe the longer you keep it, the acid content increases. I'll just juice them from now on, no more eating. Does anyone know what caused this? Tweet