There is no fallacy, but it is not logically proven either. Rather, it is a defeasible argument.
There is no logical fallacy here, nor is there an informal fallacy. This argument is reasonable and likely to be persuasive. I personally find it persuasive.
However, while it is persuasive, it is not proof. This argument provides a reasonable reason to believe something, but it is not conclusive and leaves open the possibility that contrary arguments, especially contrary arguments which add new information could also be persuasive and perhaps more persuasive. For instance, while I don't know anything about neurology personally, quick Googling suggests that there are six primary areas of the brain which address pain. If close examination of a dog's brain shows that they lack anything analogous, that might at least persuade us that the argument you laid out should not be given persuasive weight. But, the fact that the argument you laid out is not absolutely conclusive does not mean it contains a fallacy and does not mean that it is not a persuasive argument.
More broadly, there are no fallacies or biases which are automatically inherent to analogical reasoning. Analogical reasoning is ubiquitous in law and policy discussions and frequently useful in many other areas.
However, specific analogical arguments may be examples of false analogies. "False analogy" is the name of an informal logical fallacy and essentially means that the analogical reasoning brought forward fails to account for relevant differences.
To look at your dog analogy, if you knew ahead of time that dogs lacked an analog for the relevant brain areas but you advanced your argument anyway without even mentioning that fact, then you would be committing the informal fallacy of a false analogy.
Also, while analogies can be useful, a specific analogy can be attacked by highlighting a disanalogy (essentially pointing out a relevant difference that could make it a false analogy, but it truly falls into that fallacy if the difference was known by the person making the argument ahead of time), pointing out unintended consequences of the analogy, or counter-analogy (essentially showing that a different analogy which is equally strong or stronger leads to a different inferred result). And of course, since an argument from analogy never provides logical certainty, you can always advance direct evidence that the conclusion simply is not true.