There are many reasons why there might be a white spot in pupil of eye; none of them however, sound very pleasant.
They might be related to conditions such as a corneal ulcer, uveitis, or retinoblastoma according to the American Academy of Opthamology’s website (https://www.aao.org/eye-health/diseases/what-is-retinoblastoma).
Corneal ulcers are sores on the cornea. They usually result in an eye infection. The condition can happen through scratches to the eye that worsen or may be due to dry eyes. Refrain from wearing contact lenses until the ulcer has fully healed, and ensure to follow up with an optometrist.
Uveitis is a more serious condition where the uvea become swollen. This condition can lead to permanent eye vision loss. There can be three types of this swelling in different areas of the uvea.
Retinoblastoma is cancer of the eye that begins at the retina. There is a gene inherited from the parents that cause this disease.