Skin on nose thickening for some reason, help :/

Hi guys, I've had seborrhoeic dermatitis for about 4 years now, untreated (I found it to be a minor cosmetic problem). SD spread to my nose and part of cheeks over the first few months, and half a year ago I think to left side of my forehead.
5 months ago, bump appeared on my forehead, that was itching (and sometimes I felt stabbing pain). Then few more white pimples appeared around it. They overtime went away, but for some reason skin around them started rising/swelling up. The swelling stayed pretty much same, or became slightly worse, and has spread to whole left side of my forehead, but does not itch very much.
Anyways, during last half a year my skin on nose started also flaking, which is common for SD sufferrers.
However, 2 weeks ago I have no idea what happened, probably my immunity dropped a lot. One day both corners of my mouth became cracked, and redness appeared on 1/5 skin on my nose, mainly in the middle, near the tip. One spot hurt me little bit. Redness was gone in 24 hours, but occassionally I felt stabbing pain and itching in that area. Over next few days, area that was hurting me on touch formed underskin pimple, what was also happening was that skin started rising around pimple as well, for no reason. Pimple even popped by itself after a week since it appeared (with lots of blood and pus), but skin kept elevating on another parts of nose, spread from that pimple. Right now, 2 weeks later it still keeps spreading, mainly over left side of my nose,and slightly elevating it. Skin looks pretty much normal as rest of the skin on nose (basically like skin affected by SD), but it very slightly darker, probably due to shadows, and slightly elevated.

As far as I know, I have only seborrhoeic dermatitis, but can it lead to skin thickening? Or could this be related to my forehead (dermatologist diagnozed it as either acne, or folliculititis, but from the pictures I found on the internet, it looks to me like linear scleroderma) ? What am I developing on my nose, rhinophima, or scleroderma or something completely different? Or should I not be concerned?
Thanks guys.
These pictures show change throughout days. First picture was taken on 5.2.2015, second and third on 8.2.2015, and fourth today.
Red area on nose appeared on 28.1.2015, pimple few days after that, and popped on 3.5.2015. SD is evident on my pictures.
Does anyone have any idea what is going on here, with me? Thanks.
http://i57.tinypic.com/25a1csi.jpg
http://i60.tinypic.com/15wnyiv.jpg
http://i57.tinypic.com/334q5w7.jpg
http://tinypic.com/view.php?pic=dcfwv9&s=8#.VNjHwi4unIV Tweet