Oil it or needs re-blueing?

[u/AHangryBeaver]

Bought an heirloom shotgun and it’s been fine for a few years, this summer was brutally humid in my house and I took it out for a 6 month checkup/dusting and noticed pitting and rust on the barrel.

Would a re-oiling and dehumidifier fix this or should I get the barrel re-blued ?

(Using 3 in 1 Oil rather than a gun specific oil - should I use something else?)

[u/Green-Outside9301]

I’d probably try and hit it with oil / steel wool. See how it looks after and decide from there.