Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.

As Muslims, we are ordered to guard our mind of impure thought and whisperings as best as possible. We should read the last three surahs of the Qur’an at least once before retiring to bed while always seeking refuge with Allah from the whispering of Shaytan whenever we are faced with evil thoughts and suggestions:

Allah tells us to say

Rabbi a’oodhu bika min hamazaathi al-shshayaatheeni wa ‘aoodhu bika rabbi an yahdhuroon

(My Lord, I seek refuge and protection with You from the evil suggestions of the devils, and I seek protection with You from their presence around me).

Imam Ghazali teaches us that we are not accountable for mental chattering; however, we are responsible for thoughts that we nurture or upon which you dwell.

So, ask yourself are these thoughts mere mental chatter which you do not dwell on; or are they more than that or ideas you focus. If the latter is the case, then you are accountable; you ought to repent and ask forgiveness of Allah.

You may refer to the previous answer posted above on some of the Du’as you should read.

Almighty Allah knows best.