As you probably know, your body induces a fever to kill off bad stuff.
It can absolutely be part of a healing crisis where the body has just decided that now is a good time to fever.
It could definitely be related to OLD stuff that needs to be cleaned out. Our body stores stuff in our fat and it can stay in there for years! Clean it all out and be done.
However, if it persists or gets too high it could be indicative of something more serious. And for that of course you would want to seek medical advice from your health care professional. We cannot give actual medical advice, treat, diagnosis or prescribe.