Rust(?) on rear wing (quarter panel)

[DizzyDatsun]

I have three very small areas of what I imagine is rust under the paint surface of my passenger side rear wing. Under previous ownership, I think this area was subject to a repair as there are also some bits that look like thin short grooves (filler?) I suspect the job wasn't done too well. There are some acne like bumps too. Attached are some not very good close up photos. Could it be rusting through from the inside 

The largest area is about 6 x 3 cm whilst the other two are about 3cm circles. The acne pimples are about 3mm across.

 

I'm wondering what my options are. What do people think? Is it worth taking to a body shop for strip repair and respray (cost?) or can I replace the panel? Has anyone done such a replacement, if so how hard a job is it? Is it important to make sure I have good wax coverage in this area to stop moisture getting it through the paint surface? Any thoughts welcome.

 

Grooves and acne:

 

Patches:

 

 

[ilogikal1]

Well, that's definitely been painted before. And terribly! The patches look like it's just a poor paint job, but if the paint is that horrendous I suspect any repair work under it will be equally as poor. I can't quite tell from the picture what the grooves and acne are likley to be though.

 

Rear quarter panel is a big job to replace as it needs to be cut out & welded back on - it's not a bolt-on panel.

[DizzyDatsun]

Thanks  ilogikal1, I've owned the car since 2009 and only just noticed the smaller two patches. I didn't notice the grooves when I bought the car but perhaps I was dewy eyed at the time.

 

I'd be happy if the patches are poor paintwork and not corrosion as then it's not going to get any worse.