I am very new to owning rats (two males), only had them since Christmas (gift for my son) anyway I'm a little concerned as one of them has a really big lump under his neck! I've read that cysts are extremely common in boy rats? He also has a little bit of what looks like dried blood on his nostrils and a couple of blood spots on one ear. The other one sneezes constantly but I've taken him to vets and they ruled out a respiratory infection. Both of them have red spots all over their tails too. Both are behaving normally, running around lively and climbing etc and both are eating/drinking fine! Any ideas? Thanks in advance x