Garlic juice contains a sulphur bearing compound named allicin. Even though the bacterium that causes pimples is resistant to antibiotics, allicin can effectively reduce the pimple by eliminating the bacteria. Allicin is responsible for the garlic's pungent taste and smell. Although this chemical is responsible for garlic's therapeutic qualities, it is extremely strong and can burn and irritate the skin. Since a pimple is already inflamed, applying garlic juice to it overnight has caused your skin to receive a chemical burn.
It is a common (and tragic) misconception that you need to keep the garlic juice on your skin overnight. Since Allicin is an extremely potent antibacterial compound, it is effective even if you apply it for just five minutes or so. Although this method will take at least two or three days to show satisfactory effects, it will not cause any inflammation or scarring. Do not rub the mashed pod to your face instead apply a drop of the juice to the pimple as a spot treatment. Rubbing your pimple with the garlic pod will chafe the skin around it and the garlic juice will then cause an inflammation. Eating a couple of garlic pods everyday will help to prevent acne.
I suggest that as of now you concentrate on reducing the inflammation and pain. Cucumber juice is extremely soothing and so you can use a little freshly grated cucumber as a poultice for your face. Carrot juice is commonly used to treat sunburns as it helps to reduce the inflammation, therefore you can use a little carrot juice along with your cucumber poultice. You can also crush a few fresh mint leaves as the juice will help to relieve the pain. Splash your face as often as possible with cold water and use a towel to pat your skin dry.
answered by G M