Hello,
Since you are getting intense itching that is leaving scars, now your cousin is also experiencing the same symptoms, commonly it could be
scabies and is very contagious. You are suggested to wash your clothes and bedding in hot water and
Savlon frequently. Do not share toiletries. Avoid addictions if any. Do not keep skin dry, apply herbal moisturizers or ointment
hydrocortisone for relief.
Apply ointment Ascabiol on the area of your affected body & leave it for 40 minutes, after that take a bath. Repeat this after 12(twelve days), it should clear out. Your cousin should also do the same. However, other medical conditions that can cause similar symptoms are
contact dermatitis, fungal, bacterial or parasitic infections or
allergy.
To stay on the safer side get STD tests done, if its positive, you will be treated accordingly. Take antihistamines to avoid symptoms due to allergy. Get in contact of Pest control, get your house fumigated. You can also fumigate your house with herbal spray like garlic mint spray.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Nupur K., General & Family Physician