Hello. Chrysals are tiny lines usually across the belly of the limbs of a bow, either straight across or on a diagonal line, which form when the wood has collapsed in on itself by a small amount. They can occur in any wooden bow if or when the wood becomes over-compressed in one small area, usually as a result of tillering which is not perfect. Your bow looks quite good in this respect, but as with any wooden bow you should check the bow over each time you start or finish shooting it. Ash is one of those woods which are very very tough, but it is prone to chrysalling in time - sometimes not for thousands of shots though. Once a chrysal or set of chrysals occur there is nothing that can really be done, as the damage goes down into the wood of the limb. If they are not too severe, the bow will usually keep on working, but may lose some shooting speed and take a little set. If they are bad, you should retire the bow and make another one - that is the beauty of making them yourself
If you google the word 'chrysal' you will find some images illustrating what they look like.
I hope that help!