Sounds great! Tinnitus that is 3 weeks old is considered very "young" and fades away in many cases. It seems that you are such a case, so you're extremely lucky, you can expect the noise to go away.
However, consider this a warning from Nature. Your ears are weakened. The next time you get tinnitus, it'll probably stay - we have seen this many times on the forums. So commit to taking very good care of your ears from now on. I recommend reading
@Bill Bauer 's list here:
https://www.tinnitustalk.com/thread...eone-else-who-has-tinnitus.26850/#post-307822
Consider yourself lucky, take excellent care of your ears from now on, and you'll be fine.
By the way, what do you think caused the noise? Were you exposed to loud noises recently (e.g. concerts, gunshots, etc)? Are you a frequent headphone user? Did you go on new meds (e.g. antibiotics) recently? Did you have an ear infection lately? In my experience, these are the most common causes, roughly in this order.