The shock wave created by the .357 Mag is much more damaging than that of most other handgun cartridges. Combined with close proximity to flat vertical surfaces, and being indoors, you probably caused permanent damage. However, the ringing will
probably subside within the next day or so.
While in the military, my room mate thought it was a good idea to bring a simulated grenade home from an exercise (we often participated in OPFOR exercises), and the genius decided to play with it during a power outage. Long story short: He had to
quickly lob it out the back door, onto our back porch. He didn't have time to warn me. Lucky me! The construction of the porch directed most of the blast back into the house. The only thing that saved the windows, and some of my hearing, was that all the doors and windows were open (power outage in Florida, in the summer, after all).
Every LEO in the county, and nearly half of the base police personnel responded to the "house explosion" 911 calls. That idiot was reprimanded, discharged, and back in his home town within 10 days.
I was deaf for two days, and my ears
hurt severely for 4-5 days (ear drums weren't torn, but I'm sure they suffered damage the docs couldn't see). After about a week, my hearing was back to acceptable levels, but the ringing lasted for months. Six months after that sim-grenade went off, I went in for a hearing test. I lost 15-25% of my hearing, across all frequencies, from that single incident. (I had a test about a month prior to the detonation, that was used for comparison.)
As dramatic as that example is...
I am more susceptible to hearing damage now, than before that incident. The docs warned me that it would be easier for me to damage my hearing, than it was prior to the sim-grenade, but I never really believed them. Then, of course, I found out the hard way. I fired a quick string of 5 shots of 8x57mm Mauser, in a dense wooded area, with no ear plugs, on a rabbit hunting trip the next year. It took almost 2 weeks for my hearing to return to what seemed normal. At the next hearing test, I had lost another 5-10% across the most important frequency band (human voice).
Once severe damage occurs, it accelerates further hearing loss.