Marketing sticker on Medical Device outer box?

Dear Team,

A short one linked to Medical Device labeling, if you allow me:

My products are medical device class III in Europe and class II in USA. I sell it in Europe and in USA already.

For Marketing purpose, I would like to add a small promotion sticker on the front face only of the package outer box. The sticker will be only placed on the package front face. Here are examples of the sticker:
https://www.freepik.com/free-vector/collection-quality-golden-stickers_1137198.htm

This sticker is a small icon and will not hide any other information of the packaging. All the mandatory regulatory icons and symbols will still be visible on the rear face of my package outer box (as it is today).

My questions to you:
1-Do MDR and FDA allow to have small promotional sticker like this on the package front face of medical devices?
2-If yes, are there specific requirements for the stickers?
3-If yes, do the entire package (with the sticker on) need to be retested in terms of biocompatibility or other tests?
4-Would you have the link to the MDR/FDA chapters/texts that address this topic?

Thank you very much for your support on this.
Thomas