First thing, your hands are clean and your testing strips are in date? Were your levels unusually high earlier today? I'm going to assume yes to both those questions.
Have your diabetic clinic explained how much to inject when you need a correction dose of insulin? If they have, then do it.
If not.....(and I am guessing this is the case).
Ring 111 and ask for advice. (Don't wait till the morning)
The risk for T1s with high blood sugars is if they are combined with high ketones. At this point you can get diabetic ketoacidosis (DKA) which will end up in you being stuck on an insulin drip in hospital or dead if you don't get the correct treatment in time. Test your ketones with a meter or urine testing strips if you can, because if they are low or zero your high bg reading is less serious.
I''m assuming from your previous posts that you are a slow onset T1 who's probably been on a honeymoon for a couple of years and not needed much insulin. I'm guessing your insulin needs have now gone up and you need more.... But overdosing is as dangerous as underdosing so you need to inject the right amount, we can't advise on dosing here.