Hey,
Good advice given. There is no question that there is something wrong with the husbandry when ever one of your animals comes down with something, like URI, and a subsequent, Stomatitis infection, which is secondary to the URI. Either way, you will have to treat the two pretty radically, to effect any change in its health. There are various ways to treat this, but without the necessary meds, your chances of getting it well, are rather difficult at best. You might be able to get your vet to call in for a prescription of antibiotics, or he might be able to get you the drugs, directly from his office. A good antibiotic to work with, with little side effects would be Amikacin or Ceftazidime, the latter being a little pricey. See if you can get your local vet to prescribe the antibiotic along with several doses to treat the URI and stomatitis. There is a company that I order from the does mail order antibiotics, however, the vet needs to call in the necessary prescription for them to release it.
Also, Enrofloxacin (Baytril) and Cipro (Ciprofloxacin), comes in an oral liquid form that is given PO, by mouth, and works great. This might be the easier route for you to take if you don't have the experience administering injectables. Again, if there is nothing that a vet will do this would be your only other option.
Send me your Borneo's weight, and I'll send you the appropriate dose for its weight.
-Angel
-----
In life you can fall many times, but you're only a failure, if you don't try to get back up!
Evil Canevil