I have had a thick coating on my tongue for over 1 month now and 3 different dotors told me that they didn't know what it is. My new doctor took one look at me and said yes that a oral yeast infection and it comes from taking or mixing antibiotics which the doctors had me doing and the oral yeast infection came from that. He perscribed a medicine call nystatin 100000. The medication I didn't think did anything for me it only said to use 4 ml 4 times a day which is the equivalent of 1 teaspoon. He said to swish and spit it out. After 2 weeks I still have this oral yeast infection so I have no clue what to do or how long i should have been swishing for.
I noticed also a white coating on the back on my tongue and two bumps on the sides. The doctor said he didn't see anything abnormal at all. As worried826 says, it seems that I didn't stick out my tongue out so far till now.
Sounds normal to me. Most people have a white coating, especially on the back, you just probably never noticed it before until you stuck your tongue out so far in the mirror.
Seeing an oral pathologist or oral surgeon is advised.