Bathroom remodel done well, not quite
If you go to apply for a permit for work you already did, you might get one of any number of reactions, ranging from, "just pay us our fee and go away" to "an inspector will be out next Thursday to make sure everything visible looks fine (and just pay us our fee)" to "you need to rip out all the finish materials so our inspector can look at the plumbing and electrical work, and then hire a licensed professional to do the repairs (and also, just pay us our fee)".

If you decide not to go this route and just enjoy your new bathroom without telling anybody (oops too late, now it's on the internet), then the consequences will be that you'll have to disclose the un-permitted work if and when you sell your house, and your homeowner's insurance may not pay to fix any damage cause by your work that you file a claim about, should such a situation arise. Otherwise, relax and enjoy your new bathroom--assuming it was done well and to your satisfaction!

The meta-answer is that this is a DIY site, and probably 90% or more of what people ask about here requires a permit that is never obtained. Virtually every house has or will have major un-permitted work done on it during some state of its lifecycle. Don't let it keep you up at night.