i feel that the rhymes are a straightjacket on you here. obviously one can take it as either/both literal/figurative flames.

your rhymes fall flat: heart/apart, sore/more, blaze/haze, away/pray don't really excite too much. i always refer poets who want to rhyme to rhymezone dot com, which can help you work real magic.

i don't really think of flames tearing anyone apart. jackals perhaps do that. likewise "Her heands are red, her wrists are sore" seems weak, throwing a bone to a rhyme that's also weak. And if you want to keep the illusion of a real fire, then should her scream be silent?

but then, if this is all internal, do any of the spectators "understand her agony" in the slightest?

so i would tighten things up.

As I said before, not really your normal style, but I really love it nonetheless. The last stanza is eerie. Love ya.