Noticed yesterday as sunshine was bright in bedroom when putting sports bra on had puckering on left breast (arms in the air). I check regularly as have family history, but not noticed this before.  Checked again in different mirrors and wasn't visible, but was where the light was bright. Booked appointment with GP, they said they couldn't see anything (which I expected as can only see in certain light), they weren't going to refer me for breast screening until I was adamant they looked at it in different lighting  conditions, they then saw what I saw, now have referral to breat clinic. My point is you know your body and sometimes push the fact!  Hopefully it's not anything, but best to get checked!