Currently Being ModeratedNov 9, 2012 1:36 AM (in response to patnj)
I found that the network information was erased. I simply typed in the missing APN in cellular data and got the personal hotspot link back. The link used was Settings --> General -->Cellular--> Cellular Data Network
This way all the old passwords for wi-fi connections remain intact.
The alternate way is to Reset cellular settings but this way all store wi-fi passwords will be erased.
Currently Being ModeratedNov 9, 2012 2:17 AM (in response to patnj)
go to settings>general>mobile data> and scroll down to find personal hotspot
turn it on to use. all your settings are still there.
Currently Being ModeratedSep 12, 2013 1:43 AM (in response to patnj)
I switched Data Roaming back on and my Hotspot option returned.