FWIW, here is my 2 cents on this topic:
If this is the first time you have experienced the ringing, you should be fine and it will probably go away in a couple of days. If this is a recurring problem then you might have the start of Tinnitus as stated above. If the ringing doesn't stop, I would suggest getting it checked by an ear doctor. I would also make sure you don't have any wax buildup in your ears, which is an understated culprit of the need to crank things and/or boost frequencies.
For me personally, I am very protective of my hearing. Back in the 80s, I attended a concert with Poison opening for Quiet Riot (ahh, those were the days) and it was so loud that every time Bret Michaels screamed into the microphone the room would turn on funny angles because the high volume was throwing my equilibrium off. My hearing was shot for almost 3 days. I have been wearing earplugs to concerts ever since.
I have been exposed low guitar volumes for a long time, with some moderate levels, and the very rare ear-crushing levels. I've had my ears checked multiple times and the doctors are usually surprised that my hearing is actually pretty good (as soon as they hear you are a musician they usually write you off as being deaf). I only have lost the utmost extreme lows and highs - probably from sitting in front of my studio monitors for the past 14 years.
So what's my point? You get one set of ears in their natural state, so do your best to treat them well. If something ever seems too loud it probably is. We all love music, and as guitar players we like them loud, but if you want to be able to hear it in all its glory for years to come you really have to avoid overdoing it on the volume. You should also take frequent breaks while playing, even if you just reach over and turn the volume down for awhile.
Sorry if I sound like a lecturing parent (not my intention, believe me) but a lot my friends and my dad who all played in bands years ago can't hear squat now from all the years of exposure to loud music without ear plugs. I actually feel sorry for them because they cannot hear music in all it's glory like I can.
As much as I love loud music, I love my ability to hear well even more.
Just sayin'