Bubbling scales on the belly?

[Gocntry]

If you can not get your snake to a vet quickly, Mountainside Medical will sell silvadene (silver sulfadiazine) online w/o a prescription. It is better for snake burns than the petroleum-gel based antibiotic ointments.

Is it worth buying a bottle of that to keep on hand, as a just in case? Or does it expire pretty quickly?