I got a black spot on my tong ? ASAP should i be worried ?

I got a black spot on my tong i just noticed it at school friday in the bathroom. I am not sure if it was b/c i was on antibiotics for a cold or not, i do not take it by mouth though long story. I am not sure if it still there or not we just stopped the antibiotics a week ago i think not sure.|||go see a doctor or a dentist