Have you tried to reboot your device? on/off + home button. hold down till you see Apple logo & let go. (ignore the "slide to power off")
My SiL updated her iPhone4 to iOS6. She lost her contacts "EDIT" function (top right corner of screen on a contact) as well as her contact search from the phone app. I told her only way to rectify the issue was to do a restore thru the comp/iTunes.
I know, you don't want to hear it, BUT it may be the only option that you'll have to do a restore again. A member here, i recall when iOS6 was released, had upgraded. Had an issue - cant remember exactly what, but she had to restore twice to have the iOS load properly & correct the issue she was having.
This is where mine is, and I'm on Verizon also. It disappeared one time because VZW was doing something with the plans. If yours isn't in this spot, my guess is Verizon has somehow messed up your billing plan. Use the previous poster's solution to locate the settings and see if you can turn it on. If you can't, take it to Verizon and have them check the status of your plan, since all of them should now include the hotspot. Are you on their new or old plan? The one with unlimited data? If so, then that didn't come with the hotspot, and you may need VZW to reset your account, then reboot your phone.