Question about my yellow bellied slider/river cooter

[dfo37]

I recently bought 2 turtles within a week apart. I have a yellow bellied slider/river cooter and a red eared slider. They get along well, they eat well and they bask normally.

I noticed an orangey-yellow bump on the back of the yellow bellied slider/river cooter's head or neck. It seems like it might come off, but I am not sure. I know it was not there yesterday. Does anyone know what I can do to figure out what it is? Or know where to find information about it? I would really appreciate it!

[BRIZZY]

I don't recommened ever housing any 2 different species together, nor eve any same species together.

You should locate a "good" reptile vet in your area, preferably one that has worked with turtles and take them both for check ups!