How long does it take for chicken's leg scales to recover from leg mites?

[It_is_I_Rae]

This isn't an immediate emergency or anything but I treated my birds for leg mites (topical ivermetcin and Vaseline) back in January and some of their legs are still kinda scaly. Is this a sign that I didn't completely eliminate the mites or does it just take a long time to heal? Should I treat them again to be on the safe side and do mites become resistant to ivermetcin?

 

[Wyorp Rock]

Can you post some photos?

 

[It_is_I_Rae]

Can you post some photos?

 

[Wyorp Rock]

I would rub a little vaseline into the scales once a week or so.