VET BILLS! CAT HAS MOUTH PAIN AND POSSIBLE STOMACH CANCER!!

My cat has a very painful mouth (severe gingivitis / POSSIBLE periodontitis + tooth resorption) which has made eating VERY painful + has caused weight loss

All I knew before I checked his medical records that I recieved today was "inflamed gums", I had no idea it was SEVERE. The previous vet a few days prior told me his mouth was 100% healthy and shut down my concerns about mouth issues! Why would they tell me that???

Good God!

His appetite is fine but the pain from his gums makes it difficult for him to eat. He has not lost interest in food. Can only eat liquids! Has lost a couple pounds!

He ALSO has an unidentified mass in his stomach, which they found the other day. (28th May)

Stomach mass isn't confirmed to be cancer or anything yet - need a proper diagnosis ASAP! It doesn't seem to be causing any symptoms (yet?) - no lethargy, no loss of appetite, no diarrhea, no vomiting

One of these would've been possible to deal with on my own, but BOTH of these I need help with FAST!

I am aiming for tooth cleaning + stomach mass diagnosis at the very least. My poor poor boy. I promised him he would live till 20, and I am not letting money troubles stop me.