It's not unusual for Jess to need a lot more insulin if she is unwell, and even after the temperature and illness settles it can take a few more days for readings to return to normal. Often shortly before we notice any signs of illness she'll get elevated bg readings, that's usually a sign of her coming down with something. A temperature can be caused by a viral or bacterial infection, if it's a viral infection then usually doctors just say the usual advice of go home, take Calpol to control the temperature and wait it out. Unfortunately with a viral infection there's not a lot that we can do apart from keep at the extra insulin to bring readings down and closely monitor the ketone levels. If they get too high you need to get help, advice is usually above 1 contact DSN, at 3 or higher you need to go to hospital for help. They can change quickly though, Jess went from 1.5 to 0 in a matter of a couple of hours, therefore the advice to keep checking every couple of hours. When you're using a rapid acting insulin to correct high readings for illness often you need more insulin to make the same correction compared to when your child is well. Other thing to check is that the insulin hasn't gone bad for some reason, have you tried putting a new cartridge in to see if that makes any difference? We've had hot weather recently and maybe it's had an effect on it's efficiency? Otherwise if you're still worried yes definitely take him back to doctor or speak to your DSN again and get further advice. I hope he feels better soon and his bg returns to normal, I know how frustrating it is when you're doing those corrections and they don't seem to have much effect. You're doing the right thing by keeping him off school, you wouldn't be able to monitor closely or correct when he's at school.