CRV rust - welding or not?

[gman88667733]

I have a 2002 mk2 CRV, relatively rust free and I had been keeping a good eye on it. But today when cleaning, I found that the passenger side rear wheel arch has some rotten areas where mud and grime sit.
I’ve taken the trims off and the rust that I can see doesn’t go back far, but there is a section in the 2nd photo I’ll upload that is also clearly rotten, but I have no idea if it’s just a little.

We really love the car and have put a lot into it for maintenance and know the car well. In this situation, do I just get it fixed now before it gets worse and move on?
Cheers

[gman88667733]

The second image didn’t seem to upload, so I’ll add it to this

[gman88667733]

Okay... so I decided to have a go with the screwdriver and the second image soon ended up as

[gman88667733]

Just to update this - been to my usual garage and he has quoted £150 to sort it all. He had done welding for me before and has done a good job, so I’m going to go ahead with that. At least it’ll be sorted then.

Cheers