White bump/lump on my dogs ear.

My brothers little chihuahua has a bump behind his left ear. The bump  is a whitish color and looks like it is irratated cuz it is pink around the bump.
I keep telling my brother to pop it he said he already poped it but now it is bigger then before and looks irritated .
I was wondering if he should try to pop it again or just leave it alone?
What should he do?
I can tell that it is bothering him cuz he walks around all day slipping his ear like if he has something in his ear but he doesnt its the bump.
Pleas help if anyone knows what this is and what i should do please write me tell me what you think.
Thank you so much,
Monica D. Hawkins

[ginger899]

Could this be an abscess? If he got a scratch or small injury that could form an abscess. Sometimes you can pop it and it re-forms because the 'root' of the abscess is deeper down.
Best to go to the vet because if it is, he might need it professionally drained & antiseptic wash, or antibiotics.
Or this bump might be something else entirely, but it's best the vet sees it if it's causing him discomfort & won't go away.