If you are allowed to appear in Neet, then your 12th marks will not be judged further.
But u know those marks may be needed in preparing state merit list as I took a glance at various state's merit list, they prepared Neet merit list of their state by not only Neet score but also marks in 12th in various subjects.
Moreover, famous inst like Manipal(KMC) needs 60% at least in PCB and more in English. so, actually in Neet overall merit, u do not need your 12th marks(if u are already allowed 2 appear in Neet ) but it may be needed in making state merit list (Also not for every state).

Thank you