So you just updated to iOS 5 and you find you have a problem -- you go to use Wi-Fi Personal Hotspot feature and... it's gone?! Don't fret. Stop cursing. It's happened with previous upgrades too. Truth is, It's not really gone, it's just hiding, and here are a couple things you can do to coax it back.
Look for it where it lives.
Once it re-activates, you should find it back where it was before, on the first page of Settings.
If that doesn't work, it's time to escalate reset the Settings.
Wait for your iPhone to restart, and if you still don't see it, repeat Solution 1.
That's a lot but that's it. You should have your Personal Hotspot back up and running. If you've experienced this bug and used these solutions, let us know how they worked for you. If you tried something else that worked, let us know about that too!
For extra help, jump into our iOS 5 Forums