Antibiotics always tend to make the mucus worse, as the body is trying to defend against toxins from the use of antibiotics.
Undecenoic acid doesn't create die-off, as die-off only comes from killing the fungus and flooding the body with its toxins.
Many people interpret inflammation as die-off, so then it's a matter of determining what creates more inflammation.
Are you taking the HCL for stomach issues?
How many bowel movements a day do you have?