The expression of tears all over the sky is usually to express one's feelings with tears after shedding tears, which can be lovesickness, lovelorn, loss, etc.
When expressing the feelings of lovesickness, tears usually mean that the person who misses you is not around, and he expresses his inner thoughts through tears.
In addition to expressing lovesickness, tears can also be used to express feelings such as lovelorn and loss. In this case, the way to shed tears may not be because of lovesickness, but because of the loss of something important or talent.
In short, tears can express a variety of emotions, including lovesickness, lovelorn, loss and so on.