Potassium permanganate powder is an antiseptic and disinfectant primarily used to clean wounds and treat minor skin conditions such as eczema, blisters, and fungal infections. It works by killing germs and helping to keep the area clean. However, it is not usually recommended for treating mouth ulcers or neck ulcers inside the body. The solution can be too strong and may irritate or burn delicate tissues if not properly diluted. Mouth ulcers are generally managed with gentle mouth rinses, good oral hygiene, topical gels and, if needed, medicines prescribed by a doctor, depending on the cause. If you have persistent or painful ulcers in the mouth or neck, it is important to have them checked by a doctor, as they may be due to infections, nutritional deficiencies, or other underlying conditions. Avoid self-use of strong chemicals without medical advice.