That picture is nothing like the grass mumps my gelding gets…and as my guy has also had severe ulcers (glandular and non glandular AND pyloric ulcers) you really need a better vet! Sure sounds like strangles to me, grass mumps is a reaction and generally a change in grazing makes it go away! Ulcerprone horses have to “graze” constantly thus my guy is on a hay net and thrown hay in his paddock when outside as he cannot be in our field! Management is carefully monitored and is not easy but can be done, but you really need a vet that is competent in equine internal medicine.
Ive never heard of aspirine for ulcers? Generally here it’s ulcergard and if needed something like sulfracate (for the hind gut). My gelding had monthly scopes for about 1.5 years along with many other meds ie, metroziozole (sp) until we got him at a healthy enough weight to go for a last ditch treatment of heavy Sulfa antibiotics, which finally got the pyloric region cleared enough I am able to maintain him on a lifelong daily omeprazole program, but he’s a “special” case! You can find my posts about him by searching. If your horse has such severe ulcers and something like strangles, she’s sick very sick, seriously get her to a good vet hospital!
edited to add…what is your horse eating in the picture? You said your horse has had a number of colics recently. If there is severe ulcers and possibly ulcers around the pyloric area the stomach will not empty and thus colic will occur. The amount of reflux they got out of my guy was astonishing and we were lucky his stomach did not rupture. Yours looks like she’s not simply grazing on a grass field but eating some kind of feed which also could be causing the ulcers to flare. Has an equine vet or nutritionist that also specializes in feeding an ulcer prone horse advised you on diet?