Sorry I'm not sure if this is in the correct place but I'm really hoping someone can reassure me!
I scraped the roof of my mouth with food and used a mirror inside my mouth to look at the damage, only to discover a cavity on the back of one of my front teeth 
My dentist is closed until 4th January and I'm worried it'll get worse before I can call for an appointment.
Is there anything I need to do?
I'm avoiding most foods/drinks at the moment as it seems fairly big.
I keep tracing over it with my tongue and can't believe I hadn't noticed it, also only saw the dentist in September and he never mentioned it then so it's developed quickly 
I'm so annoyed with myself for not noticing it and I've just spent this last month eating and drinking all the wrong stuff which won't have helped.
I'll be calling for an appointment asap but is there anything I should/shouldn't do in the meantime?