My pet rat.

Question
My female rat is just over a year old now. She's a friendly, gentle rat & has never had any problems in the past. On Saturday night, I got her out of her cage & handled her, I noticed she had a lump on the side of her belly. It's only small & it doesn't seem to be getting any bigger. It's quite hard & when I touch it or try & squeeze it, it doesn't seem to be hurting or bugging her. She's still eating, drinking & running around as normal. Still being herself, although she seems to be a bit more jumpy than usual but my mum says that could just be to do with her getting older. I've just finished my first year of level 3 Animal Managemant at college & one of my tutors have said it could be a cist, just from me describing it. She said they can live with cists without them having to be removed or checked out & she said as long as she's still eating & drinking as normal then to leave her be & monitor the lump & if it does seem to get bigger then take her to the vets. I went to handle her this morning & she yelped at me which she rarley does. I wasn't touching the lump when I picked her up so I don't know wether another part of her body is hurting or wether she just didn't want handling as she has done it in the past. I just need reassurence that she's happy & healthy. I dred to think that she's suffering or in pain. I want to take her to the vets just for a check up but my mum & my tutor have both said to wait. What would you advise? Please tell me she's happy & healthy :(
Thanks, Samantha.

Answer
As long as she is eating and drinking then she is at least thriving enough to want to live. Sometimes  they squeak if they dont want to be picked up or you just picked her up and it hurt on accident. If she continues to display signs of being in pain then I would suggest a vet visit. I cannot assure you that she is fine since I cannot see her, however, you should know exactly what you are doing being your education and I would make the judgement that you are doing what is right.