slow healing wound

I received a large laseration to my thigh 8 weeks ago approx 14" long L shape and deep enough to damage the muscle bellow. It was cleaned and stitched in theater and appeared to be healing well but after 4 weeks an area about 5" long started to scab up the scab became about 1" by 5" and seemed very thick then started to split and become very painfull the nurse sugested putting vaseline on to soften it and keeping it dressed, which I've been doing and the scab is diminishing but it stinks and is very painfull with quite a lot of discharge, It's really getting me down, I'm on my feet at work all day and by home time I can hardly walk at all and my knee swells with fluid which does dispurse when I've rested a bit. any suggestions is this normal healing??