In Star Trek (2009), little Spock gets into a fight with three other Vulcans. After the scene he is shown talking with his dad. Spock has a bruise/scab/cut whatever on his lip but it is red. Why isn't it green?
Within the scene, you can see green blood on the lip.
I have not found an image of the scab you are talking about, but it is possible that the blood changes color as it becomes de-oxygenated, much as with human blood, which goes from a bright red to a brown as it scabs over. Unfortunately, we don't know the exact mechanism of Vulcan blood, because it doesn't follow Terran examples of copper-based blood.
The Vulcans on Star Trek have green blood - green because its oxygen ferrying protein (whatever that is) is based on copper, rather than iron. So we are told early on in the Original Series. This is all science fiction, right? Not entirely. There are animals on earth with copper based blood. It isn't bright green however, but a deep blue, or perhaps bluish-green when oxygenated, and dark gray when deoxygenated. I suppose the make-up artists on Star Trek thought vivid green would be more striking.
Just for the sake of completeness, Earth does have one vertebrate with green blood, the appropriately-named green-blooded skink. However, its coloration is not due to copper, but due to high levels of biliverdin, a byproduct of hemoglobin breakdown, in their blood (and other tissues, including their bones).
Spock isn't fully Vulcan but has a human mother by the name of Amanda Grayson and while his father Sarek is Vulcan.
Yes we are dealing with syfy laws but maybe the blending of species with the two different blood types eg iron based for humans it could affect the visual colour of blood