My experience is that when a stock is under attack, it can go much lower than you expected. HZNP is firmly in Bear territory and the general market is unsettled with the nothing burger of the new Covoid varient (supposedly milder and more aggressive, so will likely help to speed up the end of the pandemic rather than cause problems).
What I will point out, as I love to do, is that HZNP is one of the most solid companies anywhere - both in debt leverage and product prospects. I'm relatively certain that investors want to find a bottom before jumping in again (and some are taking profits because the stock is still way ahead for the year). We usually have to see severe selling and recovery (maybe multiple attempts) before this is resolved. Today could be it - or maybe not, but it will come.
In my opinion we will look back at this buying opportunity and wonder what the heck - but IMHO HZNP is going nowhere but up in the long term (fundamentals are too strong for the stock to remain stifled). Do your own DD and make your own investing decisions, as always.