I scratched and scraped my knee while playing soccer on artificial grass turf. what can i do right after within 3 hours? neosporen? wash and dry?

Sure: Clean the wound thoroughly, pat dry. Wound healing is best if the lesion does not completely dry out, so you can cover with an ointment such as Vaseline and then bandage. Replace daily or twice daily for best result. Neosporin can be applied prior to Vaseline, but 2-3 applications should be sufficient to clear any significant microbial burden (usually your body's defenses are adequate).

Both: Depending on what the scrape looks like you can do both. first gently clean the wound with warm water. Dry the area well. If there is minimal bleeding put a light coat of Neosporin, Bacitracin, or Triple antibiotic ointment. Depending on what or where you are going or doing, cover with breathable, non-stick dressing. The key is to keep wound clean, prevent infection, let air in, and keep dry.