Is it obligatory to repeat the ritual bath (ghusl) after removing the dirt under the fingernail that appeared after the first ghusl, or is the aforementioned action permissible?

Mere color is not considered a barrier that prevents water from reaching the skin unless it has a palpable mass. If the presence of a barrier is only probable after performing ghusl (definition), then ghusl does not need to be repeated. If the presence of a

barrier is certain after performing ghusl, then only the affected area needs to be washed, and continuity (muwalat) in ghusl is not obligatory. It is advisable to disregard obsessive thoughts if they are present.