Answered by Shaykh Abdurrahman ibn Yusuf Mangera
I made wudu with a speck of paint on my hands, I didn’t realise until later. Was my wudu valid?
Since most paints act as barrier for water reaching beneath it, your wudu will not be considered as valid.
As such it should be repeated once the paint spot is removed.
Abdurrahman Ibn Yusuf