Wiped some blood on the wall of the bathroom. I am confused now because the painter came when we went out of the home and he painted all the home, bathroom etc. Now should I consider that he made everything najis? Because when he painted ofcourse the blood had come intouch with it as the blood was not that much visible that he may notice it! Now whenever I touch my bathrooms's walls i consider it as najis, very disturbing life I am facing. He painted everything we were not there at time of painting so maybe he removed the blood or not i dont know.

Q 'Now should I consider that he made everything najis?'
If he started with the bathroom, then yes.
Otherwise, no.

You can just wash the toilet walls.
As you are not sure about the rest of the house, you can assume it is clean.