My cat is half stray.. he was very clean and obedient.. from past 1 month he isnt coming home daily.. he visits us once in 3 days.. from past 15 days.. he started peeing and pooping inside the house which he never did before... We scolded him.. he didnt come for about 5 days.. today he came home with a swollen right front leg.. leg is swollen twice the size of normal leg.. he lets us touch his leg.. i found few scratches and wounds in his paw.. evening he did pee on sofa.. while peeing he was making some strange noise like pain.. he is terrified.. he looks completely sick.. i dont know what to do.. if he leaves tomorrow dont know when he will return.. looking at him i feel something is bad with his health.. please help me..