Pimples are a result of pore closures on the skin due to the plugs made of oil and dirt. Itching might be a symptom of your skin being inflamed. To relieve the problem, gently clean your skin with a mild cleaner, don't pick or squeeze the pimple, and use a spot treatment with ingredients such as salicylic acid or benzoyl peroxide.

Visible veins can be caused by a variety of things including genetics, physical activities, or low body fats. Though it may be alarming, this is typically a normal genetic trait. To aid the flow of blood through the vein, stay active, eat a balanced diet, and drink plenty of fluids. Should you experience any pain or other symptoms, it is best to see a doctor who is qualified to give you the medicine that is best for you. They will carefully evaluate your condition and suggest a course of treatment specifically adjusted to your needs. 

It sounds like you may have eczema, a common skin condition that can cause itching, redness, and irritation. To determine if this is the case, you should see a dermatologist. The dermatologist can recommend an appropriate treatment plan that may include topical medications, light therapy, or oral medications. Additionally, lifestyle changes can help to manage symptoms including avoiding potential triggers, wearing loose fitting clothing, and using a humidifier in your home.

The treatment depends on the diagnosis and the cause of rashes and ring marks. Rashes and ring marks can be caused by a variety of reasons such as eczema, allergy, fungal infections etc. I advise you to take your son to a doctor for knowing the exact cause and diagnosis of rashes and ring marks. Based on that, a proper treatment plan can be recommended.