small hole in c section cut

Bi
I noticed this arvo a small hole on my cut it has some think yellow /old blood colour stuff coming from it . I have been overdoing it for 2 days and I'm a lot of pain on and off since. I'm 4.5 weeks pp I have had pain on the left side since the birth. 
When I put a little pressure not a lot just under it leaks. And it's right on a big stretch mark.
The photo isn't that clear as I cropped it for a closer look. 
Any advice? My 6 week check is in 10 days should I go in beforehand? 
I thought I healed very well,until this anyway