Blue Gums and a Fever

My poor lil man...101.9 fever and I didn't notice it until tonight. Wonder how long he had it. Hopefully not the entire day. And he is getting a tooth (which is hopefully the cause of the fever rather than a virus) and the upper gum is black and blue where the tooth is coming in. Looks really painful. Anxious for the night to see if he makes it or wakes crying and miserable. And praying that when he wakes in the morning the fever is gone, bruising gone and tooth has popped.