Brandi Glanville says her health battle has gotten so bad she's hooked up to IVs nearly all day ... and she can barely eat.

The 'RHOBH' alum posted a raw video showing her IV setup, saying she's gotten extremely skinny, can't taste her food and feels like "death."

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Brandi followed up Monday with an even more alarming update ... saying she's now on IV medication nearly 20 hours a day and is desperate to get out whatever she believes is in her face.

She says the issue is concentrated on one side of her face and admits she wants to "cut my face open and just take it out" -- though she knows she can't.

Brandi says she found a doctor who reviewed her MRI and believes she knows what's wrong, but she's not ready to share that publicly yet.

As TMZ previously reported ... Brandi has spent years searching for answers over the facial disfigurement and health problems she's been dealing with.

For now, she says she's finally showing fans what that fight has really looked like behind closed doors.