s a really helpful article that may help you narrow this down. From your description, this lump
seems under the skin but erupting to a bump (bug bite
in appearance). https://www.healthline.com/health/hard-lump-under-skin#dermatofibroma To me, this sounds possibly like a lipoma. These are not cancer. If you feel this is skin cancer, again, please see a dermatologist at once. https://www.medicinenet.com/skin_cancer_overview/article.