Hello. Thanks for asking from HCM. I can understand your concern. The numbness over jaw near chin is most probably due to nerve damage. The mandibular nerve of trigeminal nerve supplies this area. Branch of it has got cut while you were operated. This sensory branch is present in skin layer so nerve can be cut very easily. As so much time has passed and it has not recovered its function, it must have been permanently severed. You should take precaution at numb area while using very hot or cold water, sharp object like razor to prevent painless burn or cut. Now coming to your complaint of rash, it could be : Fungal infection : Chemical reaction or allergic rash You should consult dermatologist and show it to him. He will treat it after confirming diagnosis. Meanwhile, you should avoid scratching it, rubbing it. Keep it moist if there is dryness. Hope it will help you. Thanks. Take care. Dr Ishu Bishnoi