Variously called Death Day, Decision day, and a number of other less kind words, D-Day was the day that the Allies began the big push from the coast of France all the way to the heart of Germany, ending WWII.
More importantly when it comes to cystic acne, tea tree oil can be harmful to your skin when applied in high concentrations. Some individuals have reported severe skin irritation and allergic dermatitis after applying too much tea tree oil, or applying the proper dose too frequently.
The chemicals in tea tree oil may kill bacteria and fungus, and reduce allergic skin reactions. Tea tree oil is POSSIBLY SAFE for most people when put on the skin, but it can cause skin irritation and swelling. In people with acne, it can sometimes cause skin dryness, itching, stinging, burning, and redness. Applying products to the skin that contain tea tree oil along with lavender oil might not be safe for young boys who have not yet reached puberty.