Peep help

We put four eggs in the incubator on 4/6/17 and two hatched on their own over the previous day. This little one is taking a while.




The pip started yesterday and it seems bigger today. I notice that the membrane is starting to look brown on the edges. I don't know enough to know what part of the chicken I'm seeing through the hole. How do I know when to help?

I've read up about what to do (hopefully I could do it right), but when to help seems to be time and experience dependent. Any ideas? I don't want to lose the chick if I don't have to.

Currently it is at 70% humidity. It got a little hotter in there in the last hour after moving the lid around, the temp is 101.1 and dropping back to a normal temp.

Thanks in advance!