The information shown in your NHS account is the same as the information that appears in your 'core' Summary Care Record (allergies/adverse reactions and current and past medications). This information is taken directly and is held from the GP record rather than the Summary Care Records system.
The decision to opt-out of having a Summary Care Record would not affect the display of this information in the NHS account as this is a direct care service.
Please contact your GP surgery to confirm your opt-out has been processed.