Comparison of values in chart field cell

I have a situation that I could use help with. I've thought about every scenario possible and have ran out of ideas.

Scenario:

The user changes, make additions, or removes information in the system. Those changes are color coded based on what they are.

However, the 'Other' field in the chart is a free range text box. It should be able to display changes, additions, and removals to the text contents at the same time. Is there any way to display the differences between the 2 sections to compare the 'old value' and 'new value' within the 'other' section.

At present, for the 'Other' field:

• User can enter any text in the field.

• This is a String value.

• Person viewing this chart currently has to compare the old and new value with the eyes. There is nothing to let the user know of the differences.