It will show up in urine (up to a month or more for regular users) and even saliva (probably a day or more) far longer than blood, so I don’t think testing yourself would do what you’re asking.
On the bright side for blood tests, it probably won’t show up in a blood test much longer than you’re feeling it, but that may depend on the exact chemical they test for (Delta-9 THC vs other metabolites, etc.) and you should do more research on that timing if it’s important to you.
I think the best thing you can do is take a good look at yourself (or even better have someone else check you out) and make sure if you do end up interacting with law enforcement they have no reason to even administer a test.
If you may not be safe to drive, just don’t do it. If you are safe to drive and there’s nothing like your car smelling like cannabis to set them off, why would they even test you?