Late Janurary 2016 I started using a new shampoo. It gave me all of these colourless bumps on my skin similar to chicken skin (I merely thought it was that). Around ten weeks after using it I decided that I wanted to have my smooth neck skin better and it wasn't worth compromising that for soft hair. As soon as I went off it these little bumps which I thought were chicken skin began to break out. 

The photos show the progression. Image one was after I stopped using the shampoo, they look like closed comdones. My doctor prescribed me differin and ever since using differin for the past two weeks (using every three days) my neck acne has been going CRAZY!! I'm not even sure if this is acne or something else because it was caused by the shampoo. 

This is the only thing I can think of: There was a chemical my skin reacted to in the shampoo and it clogged my neck pores up. Now that I've stopped using it all these little blocked pores need to open and the differin is speeding that up. Is this correct? All my derm told me was is that its acne but is my assumption correct? I never get acne on my neck, never ever, I'm a 16 year old girl and this is really affecting me. The last photo is the most recent, taken today. I was shocked at how bad it has gotten.

Any advice? 

1) When I first stopped using the shampoo and noticed I was breaking out. 

2) Doesn't really show the bumps but this is when the actual pimples started coming. 

This shows the actual spots. I was alarmed to find that there were actually black heads. This made me think they were clogged pores and I decided to listen to my doctor and use the differin. Next images represent the next two weeks of using differn. 

Diferin week one. 

Differn week 2 - now!! 🙁