"Post kiam li razis sin, lia vizaĝo sangis."
Translation:After he shaved, his face bled.
Kaj mi legis "lia vizaĝo saniĝis".
Miracle blade! After you shave with it, your face will magically be cured of whatever illness it had.
I would say that it is not correct - your sentence contains a so-called "dangling participle".
The participle "shaving" refers to something which is not mentioned in the sentence as a subject or object... it could refer to the subject "his face" but that would make no sense.
"After shaving himself, he saw that his face was bleeding" would be better as then "shaving" would apply to the subject "he".
That said, your sentence would probably not raise eyebrows in some circles and would be understood from context. But it's probably better to avoid it.
Do you think “shaving” is a participle here? I think it's a gerund.
post is just a preposition in Esperanto, not also a conjunction.
Why do we say "because it was raining" but "because OF the rain"? Why not just "because the rain"?
...it's just the way it is. Same with post/post kiam and antaŭ/antaŭ ol.
why is it: "lia vizaĝo sangis", and not "sia vizaĝo sangis". doesn't the first one mean that someone else's face bled?
The subject of sangis is the face... and si can't be part of a subject! Since it refers back to the subject of its clause.
So here you can't tell whether it's his own face or someone else: both have to be lia vizaĝo in this position.