You can merge your Guest Mode data without losing it by following the following steps:
Go to the Account tab (the person icon)
Press Merge Data To BugID. You will only see this if you are in Guest Mode.
Follow the instructions on the screen. If you set a PIN, you will need to enter that as well.
This only works on BugID accounts that have not already been used to successfully first sign into Bugs+ before.
If you have set a PIN, you can’t merge account data to a BugID when you forgot the PIN and can’t sign in (and you need to find the PIN so far) and merge the account data.