Strange metal taste in mouth

I've been having thus metalic taste in my mouth.I dont remember when IT started The earliest I remember was a month ago or so but Today it IS really noticableand earlier today on school I felt a almost bumb on my left cheek but I dont feel IT right now but usualy I try ignore these things becouse I think that I am over thinking it plus IT cost a bit to just talk to a doctor. I googled this a second ago but The causes I didn't have. I have a good diet and healthy gums so I'm a bit lost maybe I'm over thinking it and maybe IT will be fine tomorow but I didn't know I thought it would be good to ask If anyone cam help please do