Ouch...never like mites
yeah theres a organic spray for that....for tight budget, i would recommend to get a safer garden brand fungicide 3 in 1 that sell at the HomeDepot or Lowes about 11 to 15 bucks.
for high quality neem oil that sell at the local hydro store if you have one or can order online if you can afford, try to get Dyna-Gro's Neem Oil its 100 % organic and also get Dyna-Gro's Pro-Tekt for strenght plants resistance to pests and everything to make plant more strudy. I do mix Dyna-Gro Neem oil and Pro-Tekt spray on the plant weekly till 4 weeks of flowering i stop spray.
Let me know if you get those....for now just clean web off, spray this plant in the morning...give a good bath...a lot of water and drops some ivory dish soap in the spray bottle...spray crap out of the plant, on the leaves and underside too...every morning..mites will gone. Its always good to learn from mistakes , error and trials will do you good in next grow. Good luck, buddy.
happy gardening