Hun, that sounds like mastitis. Please go and see a doctor ASAP. Also keep feeding from and if need be expressing from that breast frequently. You can definitely express in a warm bath if you like.

It might also be helpful to call the ABA helpline on 1800 mum 2 mum (1800 686 2 686) for some other ideas on clearing any lumps and preventing this from happening again. The doctor can give you antibiotics for the infection, but you still need to clear any blockages.

Best of luck hun I hope you feel better really soon. If it is mastitis, antibiotics kick in pretty quickly (if they are the right ones!).