It's throbbing really bad/badly.

[sitifan]

It's throbbing really bad. (My bold.)
Source: https://mnemonicdictionary.com/word/throbbing

Can I use "badly" instead of "bad" in the quoted sentence?

 

[dunchee]

Yes.

Bad Definition & Meaning | Britannica Dictionary

BAD meaning: 1 : low or poor in quality; 2 : not correct or proper

www.britannica.com

2 bad ... adverb
US, informal
: BADLY
- He cut himself real bad. [=very badly]

 

[emsr2d2]

In BrE, the answer is no. "Bad" is an adjective and "badly" is the adverb. You might hear it from a very few people but it's definitely not common.

 

[Tarheel]

When you use "throbbing" you have already indicated that the level of pain is high.

 

[5jj]

When you use "throbbing" you have already indicated that the level of pain is high.

I don't agree.

 

[Tarheel]

I don't agree.

Then what does "throbbing" mean?

 

[emsr2d2]

Then what does "throbbing" mean?

It simply means pulsating. That doesn't necessarily indicate that it's very painful.

 

[Skrej]

It's kind of ironic that Sheldon's character says this. It would be totally in character for him to correct someone on the misuse of an adverb.

 

[sitifan]

It's kind of ironic that Sheldon's character says this. It would be totally in character for him to correct someone on the misuse of an adverb.

What does the word "character" mean in the quotation?

 

[emsr2d2]

The first "character" is literally referring to Sheldon Cooper as a character in the show. It would have been just as easy to say "It's kind of ironic that Sheldon says this".
The second must be taken as part of the set phrase "in character", meaning "behaving exactly how one would expect".