Please advise: rental house painting?

I have a rental house, rented to Mr.A.  One month ago, MrA moved out. 3 weeks before he move, MrB come and see the house and gave me deposit. MrA moved out.  My stupid hu*****and used the old painting and make 30-40 brushing spots on the walls through out.  Now MrB moved in. She complaints about the painting.  I said wait one month. But now one month pass, she said still not the same color ( you can see it under stong light).  555555, :(.  what can I do?  it is a 2000sft house, how much to paint it all over?  please help.  Or do I have to paint it allover?  Can I say not to the tenant?