Depending upon where you live or travel, the head can really dry out.

Good guitar stores sell a guitar case humidifier designed to keep fine classical guitars from drying out and cracking.

You can simulate same by taking a small (couple ounce) food container
and making holes or slots in the top. Then put a damp sponge inside and
and keep it in the case (you do have a case) with your drum.

You might also find a humidity device at a cigar store.

Check on it every so often and make sure that you're achieving the
right balance.

That cigar store will have a humidity meter that may be useful.