What if the screen of Samsung a7 mobile phone has a blue border?

According to your description:

We suggest you try the following methods:

Because you have opened some test items in the developer options, I suggest you go to "Settings-Developer Options" to check whether the test function is checked, just leave it unchecked. Example: If white dots appear, uncheck "Show Touch Location" in the developer options.

Back up your important data, contacts, photos, memos, etc. Settings-Reset (Account-Reset)-Restore factory settings (some mobile phones are set by Settings-Privacy-Restore factory settings). After the operation is completed, the machine will automatically restart.

Otherwise, in order to provide you with more targeted services, it is recommended that you send your mobile phone to Samsung Service Center for special inspection.

Samsung Service Center Address:

. Samsung . com/support/service locations . ASP

Samsung knows to provide you with high-quality solutions and answer your questions attentively, hoping to get your satisfactory evaluation.