Hello,

 This looks like it could be maple leaf blister or anthracnose or a combination of the two. This is a fungal leaf disease and both are somewhat similar in symptoms and usually are not detrimental to the tree. The only way to be certain if a tree has one or the other or both is to send samples to a diagnostic laboratory, such as Michigan State University’s Plant & Pest Diagnostic lab, and have it confirmed. They will accept your pictures. You may want to give them a call for more information at:<personal data hidden>.

Plant & Pest Diagnostics (msu.edu)

Water is very essential in keeping your trees healthy. Trees do need at least one inch of water per week when it is not provided by rain. Drought conditions add stress to the tree which can lead to pests and disease.

More information is at the following links.

Maple leaf blister and anthracnose: Two diseases of maple leaves - Landscaping (msu.edu)

Anthracnose Disease of Deciduous Shade Trees // Missouri Environment and Garden News Article // Integrated Pest Management, University of Missouri

I am including information regarding tar spot on maples for future reference.  It is too early in the season for this. 

Black dots on maple: Tar spot - MSU Extension

Trees Stressed Due to Drought? Know the Signs and What to Do | Purdue Extension Forestry & Natural Resources

Watering Trees and Shrubs | University of Maryland Extension (umd.edu)

By the way, the bumps that you see on the leaves are galls that are caused by mites and do not affect the overall health of the tree. More information below.

Maple Gall Mites (Eriophyidae) – Wisconsin Horticulture

Leaf Galls on Maple (psu.edu)

What are these ugly bumps on my tree’s leaves? - MSU Extension

Another option is to contact a certified arborist for an assessment on your trees. A certified arborist can be found by zip code at the following ISA website:

Find an Arborist (treesaregood.org)

I hope this helps you out.