In particular, the troubled singer gets candid about the nerve damage on the right side of her body, which she says is so severe she can't think straight sometimes -- and that it's left her with loads of trauma.

She's spoken about the health issue before, so it's not anything new ... but she essentially says in her post Wednesday she's digging deep to forgive those she believes have caused her suffering.

The post is about making peace with everyone -- including her parents -- who she says wronged her throughout her life.

BS says she's not trying to play the victim ... she's just being honest about her ongoing trauma, and promises to let go of her anger as she wrapped up the post -- which she randomly began with a long-winded lowdown about her IG posting schedule.

While Britney's striving to be a better person, some folks in her world are calling for her to be placed under a new conservatorship ... hot on the heels of her recent physical altercation with her BF at the Chateau Marmont, which left her with a swollen ankle.