Still weird he was not aware of the difficulties caused by the crash and has started the TT way too fast. I imagine if it was a "simple" pain in the area where he took the hit, he would know this pain is there even on the warm-up and adjust to it. Weird because he also sprinted hard on Grand Sasso stage at the end, without being forced too, as if not feeling the effects of the crash too much. But you can put that as him pretending to be strong so others wouldn't try anything yesterday, but even him yesterday talking about being able to follow Roglic if paced correctly and gaining a minute today... there was no one to fool, as there was no racing till TT and TT is raced as fast as possible anyway.
So it looks more like he was genuinely not aware of the difficulties he will have, before he started today and saw he can't really do it as he expected to do it.
This makes me think that crashes injuries are not as painful in themselves and that there is proper form drop of the whole body.
I don't think the crash would cause infection, he was completely dressed (didn't tore the clothes) and the crash was at least basically medically attended very soon (finish).
About the puss ouzing from the wound... I've tried to read (machine translation) everything I could find about that and didn't find anything about it being "black", just about it being there. I'm a bit surprised about that, since without tearing clothes, I would not expect an open wound, but from my (limited) experience with road rashes, the wounds are a bit "slimy wet" for a few days, I thought its a normal part of healing process.