did you follow the steps to amend your return here, be sure to save a separate copy for the amended return
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-federal-tax-return-curr...
The blank screen thing has been reported occasionally here not sure all the reasons and if there was a solution, but it could be some issue with a s/w update; you can try forcing updates by holding down option and selecting the TT menu and the "check for updates" option will change to "download latest updates". If that doesn't work you may want to try reinstalling the s/w. You could also try calling TT support if not already done so.
Generally if you're having to deal with amendments and reinstalling s/w etc, be sure to have a separate data backup of your .tax files and also export your return as PDF with all forms and worksheets as your official record.
