Teddi Mellencamp's immunotherapy to treat skin cancer failed.
The Real Housewives of Beverly Hills star revealed in October last year she had been diagnosed with stage 2 of the disease, and in September, she told fans her latest biopsy had revealed another melanoma and that she would be starting a new form of treatment to help her immune system fight the cancerous cells.
However, in her latest update, she revealed that the treatment hadn't worked on her melanomas.
Doctors subsequently gave the reality star two options and she chose surgery that will remove a large part of the problematic area on December 26.
Alongside a picture of the scarring on her back, she wrote: "Long story short: The immunotherapy treatment did not work on my melanomas. I had a wide excision removal on my most recent melanoma last week to see if it did and sadly it did not.
"I have been presented with a couple new options and I have decided with my doctors that the best next course of action is have surgery on December 26th to remove a larger portion of problematic area. I don't like going under and my anxiety is popping off but I have faith all will be ok and that the reason this is happening to me is because I am able to raise awareness."
She will then have a checkup every three months.
Highlighting the importance of booking in skin checks, she added: "After surgery, when god willing my margins are clear, we will continue to monitor my body closely every 3 months. In the meantime, I am so looking forward to spending Christmas with my loved ones and hope this is a reminder to book your skin checks for the new year."
The Two Ts in a Pod co-host — who has children Cruz, Slate and Dove with husband Edwin Arroyave and is stepmother to his daughter Isabella — recently urged fans to "stay vigilant" when it comes to their health.
She wrote: "Stay vigilant on getting your skin checked my friends. We can fight this. [heart emojis] @curemelanoma #skincancerawareness #melanomaawareness (sic)"
Teddi was thankful it had been caught early and she could continue to raise awareness of the disease.
She wrote on Instagram: "I have been debating whether I should even publicly talk about this or not but then I remember how every time I post about skin cancer someone else is reminded to get checked. I can't even remember if this is the 12th or 13th one.
"I am so grateful for my 3-month checkup because we caught this one early.
"This means another surgery next week and additional biopsies. As I lay here with tears in my eyes and worry, I know my kids will be up soon. I have a podcast at 10. Life goes on.
"I keep telling myself, 'We can do hard things.' We have so many beautiful things to look forward to, so if you woke up today feeling lost or scared, I encourage you to make a list of some of the things you are truly grateful for and what you are most excited about. (sic)"