Is it obligatory to repeat the prayers that were performed with a small spot of clear nail polish on the nail, which was discovered after five days?

Ensuring water reaches all parts of the ablution (wudu') is a condition for its validity. Therefore, if one leaves even a small part of what must be purified, their purification is not valid. Accordingly, removing anything that prevents water from reaching the skin is obligatory. However, very small specks that are difficult to guard against are excused, such as traces of dough.