Hi Joy Abaja,
Welcome to community.
I go through the post carefully and understand you want to make a field shown only when the current logged in user is the same as the Reviewer field.
You may try this formula:
=if([$Reviewer.email]==@me, 'true', 'false')
Below is my test:
The Reviewer column's value is Administrator.
a. If the logged in account is Administrator, then the test column will display.
b.If the logged in user is Alex, then the test column will be hidden.
Hope above can help you.
If I misunderstand the scenario, feel free to post back and let me know, I will continue trying best to help you.
Have a nice day and stay safe!
Best Regards,
Tina