My son has a lump that looks infected on the inside of his foot. i thought it was a thorn which he hasnt told me about and proceeded to take a needle to it to extract the thorn. however no puss came out and also there seems to be layers of skin.

Lump: We can't tell you what this is without visualizing it. I always wonder about plantar warts.

Have checked : Please have this seen by his doctor either in person or with a telemedicine visit. Without seeing it and knowing the exact location, it would be difficult to give you the proper advice. This could be a wart or a cyst, possibly infected. The treatments would be different depending on the diagnosis.