Sebaceous cysts

 These are very common with older bichons; my vet has advised they are common in white coated dogs.  I don't know about if the ones my dogs get are deep, sorry.  But for bichons, unless the dog keeps worrying at it (licking, nibbling, making it bleed) or it is in a place which makes grooming an issue, we leave them be.

If her harness rubs on it, can you switch to a different style harness one which won't hit any?  Just a thought.

Nikon's had a few and I've never needed a vet.  After a few weeks or months I tend to "pop" them like a giant zit and then it's gone.  He has one right now that might actually be a fatty lipoma or whatever it's called (it feels a little deeper, I can't pop it like a sebaceous cyst) but I'm just watching it to see if it's growing at all.  Even the lipomas are normally left alone as long as they are benign.  I recently had an 11 year old foster GSD that had a HUGE one (grapefruit sized) on the inside of his thigh and we left it alone. Given his age and the fact that he wasn't bothered by it, the vet saw no reason to touch it.

Freedom

unless the dog keeps worrying at it (licking, nibbling, making it bleed) or it is in a place which makes grooming an issue, we leave them be.

  Excellent advice. Jessie has had one on her chest for years. My vet drained it once but it came back. He said he wouldn't drain it again because  there is a risk of introducing bacteria, causing an infection. To the OP; you may not want to pop them anymore, for the same reason.

Dahlia has had some of them.  Two were small (on her neck area) and went away within a couple months.  She has a third in that area that is of similar quality and will probably disappear in time.  She got one on her back, between her shoulder blades and that one kept growing.  We had it biopsied and it was nothing, but it was irritating her.  We contemplated having it drained, but then she broke a tooth and had to have it removed, so we opted to have the cyst removed surgically while she was under.

In all honesty, I just tend to leave them alone.  She also has a lump on her chest that is soft and not attached to anything and has been there for over a month without getting bigger.  We're leaving that alone too unless it starts to get bigger.  We'll have the vet look at it at her normal April appointment if it still hasn't changed size.