I've use good electrical tape (softer is better), cut into thin slices. I fold the tape BACKWARDS, sticky side out. Just that tiny tip (1/16-1/4") wide of sticky does the trick EVERY TIME. Thin is the key You don't have to use ONE thin slice, BIG DENTS, may take a couple pieces at a time. Kinda like pulling a dent in panel, try to REVERSE the way it was put there.
You may also have to push the dome in to get the tape to stick the way you want, don't be to bullish, BUT don't be afraid, works every time for me, unless they are torn. The "DABBING" effect work if both surfaces are sticky. A lot of SDs are. REAL BAD smash I've used a fine dental pick and sealed the holes with polish or tiny dab of WET silicone, Flex seal works perfect.
Nail polish and a few FINE threads aught to do. If no funds are available. I've done that more than once, when I was younger. yup yup!!
The vacuum thing does work if you use the adjustment on the hose (vary the vent hole size) so it won't tear the dome off. I've seen small divots come back out, when they warm up then cool down a bit.
I've taken them apart also, lol be careful with that one. Take your time. It took me a few tries, and a couple of domes to get that one down. Thank goodness they weren't Morels or something really spendy. Easy Peasy..