Dog possibly has infected tick - should I be really worried?

[Olete32]

Dog has been with family during half term while we were away. They couldn't get a tick out, and from yesterday it's looked red and lumpy. Also dog is trying to scratch it with leg. I made an appointment with vet for first thing tomorrow - picking up dog tonight - but should I be concerned that it could be fatal? Or am I being really dramatic?

You're being dramatic. A tick isn't going to kill the dog. If it's been an unsuccessful extraction then the vet will do it properly and give the dog an antibiotics jab. Dog might mope about a bit for a day, but that's about it.

A tick won't kill a dog in the UK (unlike say Australia where tick paralysis absolutely can) but it can cause Lyme disease which is petty unpleasant.

Since you have an appointment tomorrow there's no urgency now but it would have been better if seen to earlier.

Thanks. We told the vet and they said tomorrow was fine

As well as Lyme Disease dogs can get Anaplasmosis from tick bites and it can kill them, or make them very poorly for 2-4 weeks. (Been there done that.)

An appointment tomorrow is fine IMO. I would want the dog to see the vet sooner if it starts to appear lethargic.