Spasm or blood collected outside tissues was not treated properly post injury that gave rise to knotty ridge. You have many options at home and may be you tried these too. Hot and cold treatment, stretching, massage etc. Outside home Physiotherapists, electric stimulations etc are used. To my patients I have treated with simple, safe, economic things with positive results all my life. Thats by Ayurveda. First of all they are given turmeric powder drink 1/2 tsp in a glass of milk or water (warm) daily continuously for many weeks (even two months). Then massage with Ayurveda s Mahanarayan tel (oil). Its smelly but effective. Mahanaryan oil is commonly available in India. Elsewhere get online. I prefer to tell patients to first do hot fomentation by hot water or water bag and then genitally massage over knot and nearby areas. Continuous massage over a month or two and turmeric will show you what you expect. This oil will strengthen the muscles. It may be applied on joints too for strength. It will smoothen the knot. After about two hrs or more of massage, hot water bath is advised. Lesser smelly oils like Rumalaya liniment is available, but is not as effective. Abha guggul tablets of classic ayurvedic preparation is also herbal drug of choice for such conditions. May be added with turmeric for rapid relief. Hope it helps.