rat tail /skin problem

Question

tail bump  

skin problem   my rat has a weird bump on her tell and its hard and she has weird patches on her skin

Answer
Thank you for including the images, they help a lot. It looks like you rat has mites. The lump on her tail are the mites burrowing under the tail scales and possibly causing an infection there. The marks on her skin are from the mites irritating her skin. Please Google "Mites in Rats" and see if anything describes her condition. Follow the instructions you find there for ridding your rat of mites. If you find you need more help please message me at spazrats@yahoo.ca.