Resistance is a problem. If you see some short term help then revert back then suspect resistance. You can confirm this by revisiting the substance that worked to begin with and if there is no effect then it is likely resistant.
You could try caprylic acid (or monolauric acid), neem, hemp oil (not marijuana oil), goldenseal leaf (not root). Try that for a week or two then if that does not do the trick then send me a personal message. The hemp and goldenseal leaf will stop resistance and offer killing power, while the caprylic acid and neem are killers.
Disclaimer: I am not a doctor so I cannot dispense either a diagnosis or treatment recommendations, this should be considered educational material, check with your doctor.