Sometimes a check engine light will reset itself after you fix the issue causing the check engine light and then drive around 100 miles or so.
That's been my experience with some cars I've driven as I had a check engine light come on in my car and then it was a bad ignition coil causing the issue.
After fixing the problem by replacing the bad ignition coil the check engine light eventually went out on it's own within 100 miles of driving after I fixed the problem.
However I've also driven another car where I had to have the check engine light reset by a mechanic at a shop because it didn't go out.
So if the check engine light doesn't go out after 100 to 200 miles then you may need to have it reset although if your vehicle is running okay and you can't get it reset then there's nothing wrong with leaving the check engine light on.
Other than you won't know if something else is going on with the vehicle in the future if the check engine light is always on.
I only had to pay $20.00 to a mechanic to have them reset my check engine light but it can vary and there is supposed to be a way for you to shut off the check engine light yourself without the tool but you can also buy the tool to reset the check engine light yourself.