“Do I have tinnitus?”

I recommend seeing an Ear, Nose and Throat physician and audiologist fir a hearing exam. The buzzing is tinnitus, which may be a symptom of damage to your hearing from listening too loud through earbuds or it may be unrelated. You can listen through earbuds, but don't set the volume so high. Usually on phones, there is a color change in volume scale when you go from a safe volume to a dangerous one. Keep that in mind. 

I would recommend you get a hearing test because of course you may have lost some hearing and high frequencies with that noise exposure. It would make sense if that developed and it hasn't gotten better is to try some corticosteroid medication to see if that helps to relieve the inflammation developing after the exposure to loud noise. See an ear nose and throat doctor

Tinnitus following an exposure to very loud sound is a sign of acoustic injury. If the buzzing is gone, your ears have recovered from the injury this time. However, be aware that repeated insults may result in a permanent hearing loss in your future. I strongly recommend that you reduce the volume on your ear buds and use hearing protection anytime you will exposed to loud noise, such as from a lawn mower, in the future. You want to protect your hearing for the long run. 
 
Angela R. Sieh Ceretto, M.A., CCC-A, FAAA

It would be worthwhile seeing an ear specialist and having a hearing test. Tinnitus often reflects damage to the inner ear. However, sometimes there are underlying, predisposing factors. You can use your earphones, but at moderate volume. If people standing next to you can tell what you are listening to, the volume is too high.

Robert T. Sataloff, M.D., D.M.A., F.A.C.S

It does sound like you are experiencing what we would describe as tinnitus. There are many forms of tinnitus. During these times of acoustic trauma to the ear, it is important that you avoid any further injury to the ear with any type of loud sounds at all. Moving forward, I would recommend that you see an otolaryngologist for an examination as well as an audiologist for hearing testing. You can still use your headphones after this is fully evaluated by the doctors above. However, please keep your volume lower. The people sitting near you should not be able to hear your headphones as a good rule of thumb. Additionally, you should be able to hear somebody in the same room talk to you with a normal degree of loudness to their voice and you should still be able to hear them. These are good rules of thumb with regards to hearing and headphone usage.