A simple scratch while fighting a Vampire is enough to do it.
If you act quickly, the cure is easy.
if less than 72 hours have passed since contraction).

A short distance southeast of Leyawiin you’ll see a bridge on the shore which leads to the island.
The island contains little of note except for a ruined house.
Head to the south side of the island, and you’ll find a stone well by the coast.

you could open it using the Deepscorn Hollow Key you received along with the Bloodstained Note.
Turn left in the first room, and enter theDeepscorn Cloister.
Take another left, and you’ll find a small pool of water.
Jump into the pool and you caninteract with the Font Of Renewalat the base of the central pillar.
when you obtain one, interact with the Font Of Renewal to immediately and permanently cure your Vampirism.
Obviously, you gotta first be a Vampire before this quest becomes available to you.
To begin the quest,speak with Raminus Polus inside the Arch-Mage’s Lobby in the Arcane University.
Inside Castle Skingrad, you could speak to the Steward Hal-Liurz for an audience with Hassildor.
Once you get to Hassildor, he’ll tell you to obtain a Cure Vampirism Potion for his wife.
To get theBlood of an Argonian, Melisande gives you an Enchanted Dagger.
Kill Hindaril, and you’ll gain the Ashes.
Finally, return to Melisande with all the ingredients.
She’ll tell you to return in a day’s time.
An easy place to hide is to go back into Squandered Mine.
But the quest itself isn’t complete.
You still need to take the other Potion to Count Hassildor in Skingrad.
Speak with the Steward again once there, and you’ll be taken to Hassildor.