Can you tell me how old the Boxer is?
Are there any around the mouth area?
How .far are they in relations to the mouth?
Thank you for that information. Boxers are prone to acne and it usually starts during puberty however there could be reoccuring episodes later in life. I am going to direct you to a site regarding this and there is a picture at the top of the page for you to compare with your dog. There is also information on how to treat it if it is acne. please read all three pages to get the full information.
There are other things to rule out such as demodicosis which is a contagious type of mange,and ringworm (which is actually a fungus not a worm.) along with a fungal infections. In order to determine the above, a skin scraping may have to be done.
I was thinking more of an allergic reaction to food or seasonal, however with no scratching this would not be the cause. I have found a site on lumps and bumps if you would like to read through it. I am also going to direct your question to another expert to see if someone else has seen this before.