Is It To Be Concern About Swelling And Heavy Grazing Due To A Hit?

Hi, I'm male, 28, 174cm, 77kg, prone to hayfever and dust mite allergy. I sustained a head injury on sunday morning to my nose and forehead whilst diving into a shallow pool, I have mild swelling and heavy grazing to my face but have noticed strange white opaque snot coming out of my nostrils today, I did use a decongestant spray last night but am concerned it may be something serious.