Small bumps on the inside of the neck skin can be due to eczema, filiform warts, and papular urticaria. 1.Eczema. Due to local sweating stimulation, friction, abnormal immune function and other reasons, resulting in eczema, there will be skin redness, swelling, corn-like size pimples and other symptoms, which will lead to small bumps on the neck skin. 2. Filiform warts. Due to HPV infection and other reasons, causing filiform warts, will appear in the neck of the small painless bumps. 3. Papular urticaria. Due to mosquitoes, bedbugs, mites and other insect bites, causing papular urticaria, resulting in small localized blisters on the skin, itching and other symptoms. Small bumps on the neck skin may also be caused by other reasons, should go to the hospital in time, symptomatic treatment.