Sollte ich mir Sorgen über einen Knoten hinter dem Ohr machen?

The most common reasons behind this are allergies and skin irritation. You should pay attention to the products you use because they should not contain any harmful ingredients. To fight against this problem, moisturize well and avoid using soaps and chemicals that are too harsh.

For normal sensitive skin requires a sunscreen that has a broad spectrum with at least SPF level 30. Avoid products with chemical like benzophenones and camphor because they may cause skin irritation. Consult with a dermatologist for a personalized recommendation as per your skin type and condition

You may have a fungus infection in your groin. It may result in scratching and irritation of the affected areas. I suggest you go to a dermatologist who can diagnose and cure your disease.
 

You are very unlikely to get HIV from a barber trimmer. HIV is not spread by inanimate objects like trimmers but through fluids that carry the virus, such as blood. Look for symptoms such as fever or maybe pimples but always keep in mind the probability of this happening is extremely low.

Initially, please consult with your parents. They may advise you some natural remedies or take you to a dermatologist. The dermatologist may suggest the best treatment for you depending on your age and skin type. Some natural remedies you can try for managing your pigmentation include applying a mask or use of a gentle exfoliator. 

Hair fall may happen as a result of several reasons such as stress, unhealthy diet, or heredity. You may be the one to whom it is happening if you notice more hair on the pillow or in the shower. To support your efforts, healthy eating, stress relief, and using gentle hair products can be helpful.