My 10yo has mild asthma buy recently has been worsening requirng more frequent puffs, what can I do?

See the doctor. Worsening asthma symptoms, even when mild, require an office visit to properly adjust the medication. Asthma is categorized based upon the severity and frequency of symptoms and management is tailored to the category. There might be other reasons, like infection or allergy, that could be impacting the asthma. See your doctor soon.
Asthma problems. Asthma is a complex disease that requires thorogh investigation as to the cause in a specific individual. Consult a physician who is well versed in the diagnosis and treatment of asthma and develop an on going treatment plan. Frequent re-evaluations are necessary to optimize treatment. Follow your physicians instructions carefully concerning what you can do to help.
Asthma TreatmentPlan. Lots of good advice so far. I'm going to add that an asthma treatment plan is a useful tool for controlling asthma. A plan is an agreement between the patient and the treating physician of what medications will be taken when feeling well, how to recognize worsening asthma & what to do about it, and when to see the physician. Plans often add clarity.
What's changed? When you use your quick-acting rescue inhaler more often, you need to change how you're using your controller medicine, which helps heal your airways and prevent asthma. Besides changing medication, it's time to play detective! Ask yourself what's different lately. Any new pets/animals? More dust, mildew, mold? Any fumes? Secondhand smoke? More colds lately? Any tummy troubles [heartburn/reflux]?
May need more meds. Please go see your pediatrician for a full evaluation. However if your child is using their rescue inhaler more often it may be a sign that s/he needs more medications- specifically an inhaled corticosteroid that they would take daily. This has been shown to lessen the daily symptoms as well as the number of asthma attacks.
Go to her doctor. The most common cause of an asthma exacerbation in children is viral infection, specifically rhinovirus (the "comon cold"). Otherwise there are numerous other environmental and host factors which may be contributing to increased bronchospasm, including exposure to a sensitizing allergen (dust mite, pollens, animal dander), weather changes, emotional stress, cold air, exercise or solvent fumes.
Rescue vs Prevent. If your child is requiring his inhaler (rescue medicine) more than 2 days a week, you should check with your doctor to see if he needs a preventative medicine. Rescue meds give quick relief, but are not adequate for good control when asthma keeps flaring up. Preventative medicines can significantly decrease sick days, er visits, hospital stays, and severe attacks. Check with your doctor.