Trust in your ability as a writer to find something more interesting to talk about than your character’s ‘perfectly manicured nails’. Even if it means describing the length of their nose hair. In fact, give them really long nose hair. It will make them more of a substantial character than one who has ‘perfectly manicured nails’ blech ick nyerr.
The only way the phrase is acceptable in a sentence would be to include it thus:
'I could not tell whether her nails were perfectly manicured because her hands were covered with blood.'