Hi Lou,
On their own, ketones pose no risk to health. They are simply your bodies means of generating its own fuel if other resources are scarce.
Ketones with high blood sugar are another thing entirely. This is a result of a chronic lack of insulin. There is plentiful fuel in your bloodstream, but too little insulin to dispose of it. If it's allowed to build up, your blood becomes acidic and very harmful indeed.
You have to get your bg down pronto. Any reading in double figures is far too high and will damage you via diabetic ketoacidosis and glycation.
It's not simply a case of using more insulin because high levels are also harmful. It sounds as if you need to look at your diet carefully and adjust things to get your bg down where it ought to be - around 5mmol/l. If you do this, you'll certainly feel a whole lot better.
All the best,
fergus