I have some kind of rash on the left side
Hello and welcome to ask a doctor service. I have viewed the image and gone through the query.
Seems like an eczematous dermatitis. I suggest you to use a moisturizer and a moderately potent topical steroid over it e.g either Mometasone furoate cream 0.1% or Triamcinolone acetonide cream 0.1%, twice daily for a few days.
Hope I have answered your query. Let me know if you need any more assistance