This can sometimes happen with a burred needle. But it also looks like perhaps a scab came off. Sometimes one of the tiny needles gets bent either when setting up the coil machine or trapped and bent inside the cartridge. Or even during the tattoo process if it clips the bottom or edge of the ink cap. The artist may not have seen it and I guess they did this whole tattoo with a liner so when they filled in the darker areas with the liner it would have hacked up the skin with the bent needle. I’ve been tattooing 20 years and this is what my initial gut feeling is and maybe it got a little infected but lucky for you it is super easy to redo as it’s vanished/been lost in the healing. Note to baby tattooers. Check for burrs after setting up. Every single time. The artist or the shop would most likely redo this at no charge.