Its been 28 Days and the eggs haven't hatched....?

....what do I do??? I cracked one open and I defenatly new it was rotted before I did because it has a shadowy growing thing on the edges of one end of the shell and nothing in it when I cracked it open. The other 7 I candled and I know some of them were alive and growing or still are because I heard of one girl whos eggs hatched on day 28. Anyway I knew because I saw what looked like a chick with kinda pitchfork feet and a head with a tiny roundish beak and a body and...damn it was cute lol. This is my first batch of eggs and I got them from Mypetchicken.com. The air bubbles are DEFENATLY still there because they are very easy to see when candled. Is it true that low temperature can lead to late hatching? Theres a bit of what looks like the inside of the egg on one of my most grown and prized eggs lol but I checked everywhere and there was defenatly not a crack. (or maybe there was and I didn't know) is that a sign of pipping? I heard a kind of clicking sound but I don't know if that was them or the homemade incubators screen. The humidity has been pretty good but the temperature varied. At some points it went down to 90F but it was usually at 95-100F and I know it should be at 100F but it was hard to keep steady. Now it's like 99F and they don't smell at all they used to before I cracked the rotten egg but now it just smells like a nursery/baby breath. I'm very attached already lol because very recently my best friend died and he was an anorexic corn snake named Biddlez and I loved him and now I really want these eggs to hatch so please help!!!