Pilea with light dots - is something wrong?

Hello there beautiful plant people!
My piles is lighter green on parts of her leaves. It wasn't like this before. Does anyone know what might be wrong? If it's something bad or not? She seems to be fine otherwise.
Thanks!

Ah, forgot the photo. Here it is.

Second photo. Some leaves are free from the discolouration.

Hmm, I am not really sure, are there any visible little bugs on the leaves or webs on the plant?

#3 There are no bugs or web on the plant that I can see. It have been like this for a while and slowly gotten worse.

Hmm maybe its just nothing. Could just be the winter light. Do you every spray it with water?

#5 I never spray it with water. I was going to ask "Could it be too much sun?" But then I remembered hey, it's winter. It's in a west facing window (I think..), could the sun be the problem anyway? Or is it more likely too little sun? I water it when it's dry. I changed the soil today.

I have no idea if it is a reflection of the plant's health but I think it looks really pretty actually with the dots!

#7 Thanks! It looks quite special.

I asked my mom and she thought it could be some type of deficiency, and then the soil change should "cure" it. I'll keep you all updated if it gets worse or better.