Hi Amanda,
Did you already perform the refresh?
If you didn't, and this is about customizations/metadata -- then you can store the current sandbox customizations into a source control system (e.g. Git), refresh, get the refreshed customizations, and compare them with the previous revision.
In order to get the customizations, you can use SDF (I'm sure the folks over
#C42JX79UZ will be happy to help as needed) or
Salto (either the open-source or the SaaS version) -- full disclosure, I'm from Salto (feel free to DM me for additional details if needed).