Need advice- new snake has RI

[Will0W783]

Ok, I just bought this gorgeous, docile male GTP on Thursday and he seemed fine when he arrived. However, he seemed a bit "hissy" on Saturday and yesterday he bubbled a bit when I picked him up. Today he refused food, bubbled when hissing again and I got him to open his mouth with a q-tip and he has thick mucus in there. I had him in quarantine at 82 ambient with the upper cage being at around 87-89 with humidity 70%. My question is, it's only been 3 days (I noticed definite problem yesterday, Sunday)- has too much time elapsed to contact the seller and ask him if he could help me out with vet bills?