All changes you or others make in feed is registered in the product change log. 

This is accessible via the contectual menu on the product (1). Then click on Change log (2)

The list of changes on a product that has been around for a while might be long (with several hundred changes). 

1. To narrow it down to the changes you are looking for you can filter the list down on "change area". 
2. Several of the filters can be filtered down further. Then you will get a second filter option, as seen on the printscreen.

Once filtered you can get a clear overview of all the changes. Field name, old value, new value, user og integration that made the changes and what date and time it changed.