I am not 100% certain, but I think that this sentence is using 得 as an auxiliary verb meaning "must" ('děi'), not as a particle ('de'). You can read more about this use in the Chinese Grammar Wiki: https://resources.allsetlearning.com/chinese/grammar/Expressing_"must"_with_"dei" There is another pattern that uses 得 to indicate an effect of a verb, so that's a possibility, but I'm not confident I could explain that correctly. Apologies for using English, but there's no way that I could explain this in Mandarin! :-( 不好意思，我的汉语水平不高，所以我必须写英文回答语法问题。

您好， Chris I only want to add a bit. I’ve learned about the basic concept how to use “得” (de) before. Perhaps, it could help you. 得 is sometimes used when you want to describe something about the the degree or the potential of an action or a quality of a thing. And, it is placed after a verb or an adjective. For examples: - 他跑得快* (*adj.) - 我跑得不快 (notice that when you want to negate the sentence, 不 is put before the adjective) - 你跑得怎么样*? (*pronouns) - 她跑得太快了* (*phrase) - 我的牙疼得很* (*adv.) My professor told me that if I could grasp how to use 得, it would be a stepping stone to a higher level. p.s.: if you don't mind, there are some corrections I made. 这个例子对不对? 这个句子本来还没完成。 课文里写的是”我的牙疼得。。。” Kindly regards, Tere

我牙疼得要去看看医生. I see no problem with this sentence. It translates figuratively to "My toothache is SO painful that I have to see a dentist". or literally, "My tooth is SO MUCH in pain that I have to see a dentist". Here 得 is equivalent, "so much..." The problem is the term 牙疼" this can be a noun phrase to mean "toothache" or 牙 as the noun and 痛 is used as the verb. If used as a noun phrase, then the grammar is wrong and so you need to have a verb/adverb such as 牙疼得要死.

你好，Chris! 你老师说得对，学中文就要多写汉字，哈哈哈~ 我同意Alex和Jack的观点，如果你非要用这个句子，我们会说：我牙疼的必须得去看看医生了！疼得要命！ 希望对你有所帮助！Thanks！

Hi，Chris! “我牙疼得要去看看医生” 这句话如果是单纯的看，是可以讲的通的，如果去掉要，就更好了“我牙疼得去看看医生” 得 后面一般是接动词的。 anyway，你说的很好，继续加油，不要局限语法，希望对你有帮助！