The key words here are use sparingly. I used some all purpose fabric glue that worked great. In the places I put it on too thick, it shows through ("stains"). The places I glued were the edges. I have spots like you have where either a syringe or cutting a slit would be an option. Kinda think a syringe small enough to put down the correct amount wouldn't be big enough to push the glue. Let us know how it goes. Maybe somebody here has a better solution. This issue seems to be fairly common.