@Wish You can get an exception from skiing in Regionals for various situations. You need to contact your EVP and provide any required documentation, and if accepted, you can still ski Nationals after missing Regionals. I got an exemption because I got injured just before Regionals and couldn't ski, but I ended up not going to Nationals anyway because by the time I could ski again, I wasn't back in form. Here is the verbiage from the rule book:
Excuses: A skier who is unable to compete in a Regional Tournament may be
excused from the Regional Tournament provision of Rule 4.02.A for the
following reasons:
1. AWSA Representatives: An individual, officially selected by the AWSA to
represent the Association at an international competition on the same
dates as his Regional Tournament, may be excused. This may be
extended to include not only athletes but judges, scorers, drivers,
delegates, and other officials.
In the case of minors, this may also be extended to include parents or
legal guardians of same.
2. Other Excuses: The EVP may excuse a skier from this requirement if the
skier provides proof, at least 48 hours prior to the start of the Regional
Tournament, that he is confined to a full-facility hospital; is on extended
military service; is on jury duty; is involved in an immediate family
tragedy; or has suffered an injury or illness that precludes him from
participating. The proof provided to the EVP must be sufficient to allow the
EVP to make a fair and objective determination regarding the skier's ability
to ski at the Regional Tournament. If the skier does not provide sufficient
documentation (e.g., hospital admittance form, jury duty notice, etc.)
within the stated time frame, the skier must appear before the EVP at the
Regional Tournament, prior to the skier's scheduled event, at which time
the EVP will make a determination as to the skier's ability to ski in the
tournament. The EVP may excuse a skier for reasons other than those
listed above, and with less than 48 hours notice, under extraordinary
circumstances. Any skier misrepresenting his situation to the EVP shall be
precluded from skiing in the National Tournament for the current year