Hello and welcome to the forum. If your ketones are higher than 3.0, I strongly urge you to speak to your parents. That is indicative of a serious issue. This is something that you should contact your doctor about immediately. To ask, and please know this is an anonymous forum, but do you have any eating disorder issues such as anorexia or bulimia? Are you on a special diet? Just asking for what additional influences on your numbers there could be. Slightly high ketones could mean you missed your insulin shot. How is that going? But you would be in the really high range it sounds at 4.2 and that really requires immediate medical guidance. https://www.mayoclinic.org/diseases-conditions/diabetic-ketoacidosis/symptoms-causes/syc-20371551
Please let us know how you are doing.
How are you going now?
Ketones can be caused by fasting, by low carb diet, or by lack of insulin.
Considering that you are posting in the T1D group, I am assuming that you are T1D on insulin. If your ketones and your blood sugars are both high at the same time and you haven't been taking insulin, then this is very concerning and you may need medical attention. Please also ask your parents or an adult for help if you need it.