Ooh, Steve. I have done the same. Not fun.

Excuse the bit of thread drift, but Steve's post reminds me - I have read some from the journals of those on the Lewis & Clark expedition. Along the mid and further reaches of the Missouri River where portages were necessary, prickly pear was common. By that time boots had worn out and most of the men were reliant on elk-hide moccasins, which provided little protection from the spines of the prickly pear. Caused crippling hardship, suffering and delay in the party's journey to the Pacific coast. Many journal entries regarding this.

To bring it back around to topic, never wade through prickly pear thickets without thick, hard boots.