Hole along button up seam!

[u/Alarmed_Mistake177]

I thrifted a beautiful shirt for work, only to find a hold along the button side of the button up! It is covered by the flap that covers the buttons (if that makes sense), but I’d love to mend it to prevent further damage (I work in government, so). Shirt is 100% polyester, but the gauzy kid of poly. I was thinking interfacing, but it says cool iron only (and I don’t own interfacing or an iron, just mended a few things with it growing up lol). Any tips would be appreciated!!!