What will be the consequences if the thorns are not picked out?

If the piercing is not deep (within about 2mm), the thorns can be expelled with the keratinization process of the skin. But if the stick is too deep, the body will treat the thorn as an antigen when it hurts the dermis or even the subcutaneous tissue. Phagocytes will act, and there will be an inflammatory response in the wound. Fibroblasts will also activate when stimulated, forming scar tissue around the wound, which means scarring will form around the wound, and then continue to tighten, and the thorn will become difficult to pull out.