Unsurprisingly, after being deprived of all of his external senses for quite some time, the influx of information Valyr had received from it being forcefully opened caused the young man to feel a considerable level of mental pain.
If he were to compare it to something, then it would be more or less equal to the mental strain he had put his mind through forcefully pushing the entrance to the connection open.
Nevertheless, as someone who had endured such types of pain before, Valyr knew what to do and quickly shut off two of his most important senses, closing his eyes and covering his ears to allow his other senses to acclimate to his current surroundings.
Then, once he felt comfortable with three of his senses active again, he removed his hands from his ears, allowing his sense of hearing to acclimate, before eventually allowing himself to acclimate his sense of sight, opening his pair of eyes in what was quite a considerably long amount of time.