I suddenly broke out in about 100 giant hives after applying my "usual" sunscreen one day! The hives took 6 days to go away- it was AWFUL, like having a disease! So apparently I suddenly developed an allergic reaction the chemical suscreens.
Oh yeah....try to find more than one brand of sunscreen that works for you and rotate your sunscreen usage if you use it every day. Even if it is Zn/Ti-based. Using the same sunscreen every day increases the changes that you will develop an allergic reaction. What you experienced isn't all that unusual. Rotate, in general, even the Zn/Ti-based because the transport media is not inert.