So about a week ago I noticed that I had bumps on my chest that I just kind of dusted off as sweat bumps (they kind of look like goosebumps). Then one time I went to scratch my back & I noticed that I had bigger bumps on my back along with goosebumps looking bumps, they're a little itchy sometimes. I noticed the bigger bumps on my back about 2 days ago. My mom said I shouldn't worry about it. I later realized that the goosebumps like things spread more high than my chest & now around clavicle. I have them on my shoulders too. I just have the bigger bumps on my back. I have a few pictures to show what I mean. The bigger bumps are just on my upper back. I need help to find out what this is. It is summer where I live, it's been pretty hot. These bumps have never appeared on me before & it makes me not want to wear any tank tops anymore. I have never had back acne or back pimples or chest pimples, well maybe a weird chest pimple hear or there but never acne. I need help, I want to know what this is because it's ugly & it really bothers me. I thought at first that these goosebumps like things were just sweat bumps but now they're on my back & they're bigger. They don't seem to look like acne or anything, I've never had acne there so it would be a surprise. I have pictures of them but I don't know how to post them. I'm new here.
Maybe, needed info:
I'm 15 years old, I am a female who has never had body acne. & I have never had this thing before so I am clueless.