leisions on dog's toes

[funiamama]

My dog(7yr old) got sick in the middle of may,vet said it is lung infection-she was treated with Baytril,couple of days later we noticed big bump on her side,next day we went to vet again,he did x-ray on her and said it is tumor and needs to be remove as soon as possible-so we scheduled surgery three days later.Tumor was removed,she got v-drains which we cleaned several times a day.Right after surgery I noticed two puss filled bumps on her side,couple of days later she started limping on her front paw.We went to vet again,she said that t is artritis and gave her Dasuquin.Three days later she got her first leision on the paw that she was limpng.About week later she started limping really bad on her hind paw.Vet did x-ray again and said that i is caused by arthritis,said we should continue on Dasuquin.About two days later she developed another leision on the hind paw that she was limping.We went to vet again,she took samples and sent them to lab for test for: Fungal cultures(histo,blasto,etc)and anaerobic cultures.She ordered Clavamox this time.My dog has been on Clavamox for a week now and just two days ago I noticed another sore popping up.My vet just called me and said that Fungal test(histo,blasto)turned out to be negative.What is the cause of all this then?

[funiamama]

Thanks for warm welcome,so nice to hear from friendly people,especially in tough times like this.I will try to ask Dr. Cheng about my concerns.Once again thanks and my best wishes to you.

[chihuahuagrandma]

Welcome to the dog forum, there are wonderful, informative people here, so check in from time to time to see your comments...
I personally do not have the knowledge of your existing issue, but hope you find your answers...
We also have an "ask a vet forum" Dr. Cheng, maybe you can also post your concerns w/the vet...
Most of luck to you and yours, very sorry to hear about your little friend's hurt...