Teddi Mellencamp is about to snatch your wig as she snatches her own ... because she is sharing a major moment in her cancer treatment.

"The Real Housewives of Beverly Hills" alum whipped off her wig on her Instagram stories Wednesday ... to reveal her real hair growing back.

You can see in the video ... she's all smiles as she runs her hands through her light locks.

This is definitely a big win for Teddi during her treatment journey -- especially since she's had a rough few years.

She was first diagnosed with stage 2 melanoma in 2022 ... which spread to her brain and lungs last year.

In October, Teddi shared that she had "no detectable cancer" when she went to the doctor ... but recently shared that she still has 9 more months of treatment.