Couldn't comment on the color of the oil, but it would be helpful to know what oil(s) you're using and how long after eating do you pull at night.
As for growing gums, I've had some regrowth but couldn't attribute it entirely to oil pulling since I started taking lots of COQ10 at the same time (it's also known to help with gum growth).
If you have receding gums, OP helps better tighten your teeth/anchor your gums to help fend off bacteria from the roots. It also does a good job of removing mouth bacteria in general.
I went to the dentist when I was almost 40 and was told I had such a bad case of recessed gums that I would likely lose most of my teeth by the time I was 50 no matter what I did. (This was because of a REALLY stupid chewing tobacco habit I had for decades).
15 years later I haven't lost a single tooth and none of my teeth are badly receded anymore let alone having the bottoms exposed above the gum lines.