Please help me 🥺 .. what is it on her chest ... In this harmful , it is a bulb like structure inside her skin no wound is there , please suggest something to me ???

Hello Priya. It’s a thoracic mammary gland. All the mammary glands swell up post delivery. If any of the glands are swollen in excess, it can be an infection, but it should be examined clinically by a vet. You can speak to any vet online or see a vet if the problem worsens.