The prophet ﷺ used to say when prostrating himself: “O Allah. Forgive me all my sins, small and great, first and last. “ the narrator Ibn al-sarh added: “open and secret.” (Using translation from Abū Dāʾūd 878)
أَنَّ النَّبِيَّ ﷺ كَانَ يَقُولُ فِي سُجُودِهِ اللهُمَّ اغْفِرْ لِي ذَنْبِي كُلَّهُ دِقَّهُ وَجُلَّهُ وَأَوَّلَهُ وَآخِرَهُ زَادَ ابْنُ السَّرْحِ عَلَانِيَتَهُ وَسِرَّهُ