Dandruff is a fungal infection and there is not permanent cure for dandruff.

Allergic dermatitis can lead to redness, itching, and swelling in the affected area It is necessary to find out which allergen is causing the reaction and avoid it. I suggest you to see a dermatologist for proper diagnosis and treatment.
 

The little bumps under your tongue that appear and disappear might be swollen taste buds, which don’t pose any danger. Conversely, oral thrush is a result of yeast infection. This is quite widespread and can be cured with antifungal drugs that should be prescribed by a physician. Do not forget to brush your teeth regularly and to follow a balanced diet.

The red and circular patches that have spread all over your body might be ringworm. This is a fungal infection that requires specific antifungal drugs like Terbinafine or Clotrimazole in many cases. The affected areas should be kept tidy and dry; loose clothes may also be worn.

Head lice are little bugs that reside in your hair and give you an itch. The nits are the ovum of their species. Treating head lice is crucial to prevent the occurrence of new infections. Ivermectin tablets are an effective treatment although you should consult your doctor first. Shampoos are some of the over-the-counter treatments that may also be effective. The washing of clothing and bedding is necessary to avoid a second infestation. 

The penis area hair loss reason can be different. The rubbing of garments or activities is a common one. Also, psoriasis or fungal infections may cause hair to drop in that location. Use antidandruff medicine if it itches or appears red, keep it neat and dry besides dressing with comfortable clothes regularly is essential for preventing more hair fall in this region. 

Stress, neglecting oral hygiene, and certain foods can cause mouth ulcers. Usually, Omeprazole tablets are not used for the treatment of mouth ulcers as they mainly aid with stomach issues. For the treatment of ulcers, you can use over-the-counter remedies such as oral gels or rinses to reduce the pain and facilitate the healing process. Do not forget to maintain a proper dental hygiene routine and a balanced diet to keep them from returning.