Database design how to track a change on a patient row and set in a log table
When I have done similar in the past, I created a changed table. For yours I would keep the patient ID as a foreign key and then list the original value for the field and the new value for the field. You do not need to keep the whole record each time it changes, just a list of the changes. I am assuming you are not required to do so by any regulatory agency, in which case check and see what they require.

I also tracked who made the change and when. You can include a field asking them to justify the change. Good info to have in case there is a question later.