Hi there. .. I can understand your concern. Early ejaculation could be due to many reasons. Anxiety being the most. So first try relaxation techniques and distraction method. Then try to cut down on any habits like alcohol, smoking or drugs. This will help delay ejaculation. If there's no improvement then you must be investigated for any comorbidities like
diabetes hypertension hypercholestrolemia. Treating these comorbidities also can delay ejaculation. Also any associated erectile dysfunction will also have to be treated. Medically there are many options like oral medications and topical creams. If the above conservative measure do not help kindly consult a psychiatrist or endocrinologist for medical therapy. And stretch marks and ejaculation have no connection at all. Stretch marks occur when the collagen in the dermis gets stretched. This could be due to gyming increasing the muscle mass, obesity leading to fat increase or application of topical steroids. Kindly consult a dermatologist for further evaluation of that.