Hello,
If you did not make the backup of theme options there is no way to get all the options back. You can only import options from the default Underwear demo. To do this go to https://www.8theme.com/download-plugins/ and download XML files archive. Extract it and find underwear folder, find options.json file inside that folder. Open file using any text or code editor and copy code. After that go to Theme Options > Import/Export > Options > press import from file and paste your code > Import.
Regards