What you have sounds exactly like what I have.
I have perfect white circles around my moles. (the moles are actually gone now, just white spots left) One next to my belly button, one on my chest, several on my back and one on my face (near my ear)
The biggest one is around the size of my thumb nail.
I am also 26 and have had them since I was about 14 or so.
Here's what I was told about them by my derm when they first started "popping up"
It is a skin disorder called Halo Nova, and it is a "first cousin" to vitiligo.
She didn't tell me why they popped up around moles (actually not all of them did)but she did tell me that they could be an early indicator of thyroid problems (which runs in my family - so it makes sense I guess)
She also told me to be extra super careful about being out in the sun, because the loss of pigment in my skin makes skin cancer more of a concern - the skins natural protection is no longer there.
I have no ideas on how to "fix" it. I honestly stopped caring, at first they bothered me, but now they're just a part of who I am. People ask about them in the summer time(kids especially) and I usually make up a funny lie about it (oh, bleach splashed on me... or I just dabbed on some sunscreen in places...) then I tell them the truth.
But here are my suggestions to you.
1. Get your thyroid checked
2. Always wear sunscreen! If I'm out in the sun without sunscreen, my white spots get REALLY red and sometimes swollen - that's really scary! I haven't let it happen in a very long time.
3. Go to your family doctor once or twice a year (I usually go after summer) and get your skin checked. Better safe than sorry right.
I haven't been able to find anything at all online about halo nova- the only reason I started looking is because I think my thyroid might be out of whack (her prediction came true? lol) so if you find anything out about it, please let me know. I'm sure it has a medical name, I just don't know what it is - I've moved, so I haven't seen that derm in years - or any for that matter.
I was spelling it wrong, it is spelled halo nevus or halo nevi for plural, the correct spelling has really helped my search.