I was suffering from Hidradenitis suppurativa (HS) for almost 10 years. I started taking ACV when I was in the Middle East and the HS problem started. I was never able to link it to ACV. When returning back to my home country, I stopped taking ACV and the problem of HS was completely gone.
I recommend anyone suffering from HS to avoid acidic/high citrus foods such as lemon, ACV etc.
Last week I was diagnosed with hyperthyroidism and I read some papers that are linking HS with hyperthyroidism. Please do check with your doctor and do some research. I know how painful these skin problems are and just sharing my observation here.