If anyone could help, I'd appreciate it.

I've an upcoming trip from LHR-HNL and a change of airlines at SFO. Booked through a misprice but honoured.

UA are the domestic leg in this scenario, and they've just emailed me through my OTA to reschedule the flight 1 hour earlier than it should have been. It now just gives me 1 hour 20 mins to clear security and change terminals.

The OTA booked it as a full round trip but as it concerns two carriers, I am panicking now that if I inevitably miss the domestic sfo-hnl leg - the airline will be hesitant to reschedule me if they can see what I paid for the ticket.

Is 1.20 enough time to clear and change from intl to UA?
Should I go back to the OTA, and see if they can change it in advance?
Am I likely to be publically embarrassed?