Hi, Mandy! I will try to search out ulcers caused by diabetic neuropathy but I'm going out this evening plus I'm in the middle of packing for a vacation! But, I have some exercises you could do that could help your circulation. These are suggested when traveling to help prevent deep vein thrombosis. It keeps your circulation going and just might be very helpful to you. I still would elevate the leg whenever you are sitting and lying down and also would walk as often as possible, if your doctor says it's alright. Walking is one of the best forms of exercise a person can do and it doesn't cost a thing! 
Hope these exercises help you.
Sherrine
SEATED EXERCISES:
1.) Ankle Circles: Lift your feet off the floor and twirl your feet as if you're drawing circles with your toes. Continue this for 15 seconds, then reverse direction. Repeat as desired.
2.) Foot Pumps: Keep your heels on the floor and lift the front of your feet toward you as high as possible. Hold for a second or two, then flatten your feet and lift your heels as high as possible, keeping the balls of your feet on the floor. Continue for 30 seconds, and repeat as desired.
3.) Knee Lifts: Keeping your leg bent, lift your knee up to your chest. Bring back to normal position and repeat with your other leg. Repeat 20 to 30 times for each leg.
4.) Shoulder Roll: Lift your shoulders upward, then pull them backward, downward, and forward, creating a gentle circular motion. Continue for 30 seconds. Then reverse direction if desired.
5.) Arm Curl: Start with arms on chair rests, bent at a 90-degree angle. Raise one hand up to your chest and back down. Alternate hands and contunue for 30 seconds. Repeat as desired.
SEATED STRETCHES
1.) Knee to Chest: With both hands clasped around your right knee, bend forward slightly and pull your knee to your chest. Hold the stretch for 15 seconds; then slowly let your knee down. Repeat the same stretch with your left knee. Perform 10 stretches for each leg.
2.) Forward Flex: Keep both feet on the floor and slowly bend forward, reaching for your ankles. Hold the stretch for 15 seconds and slowly return to a normal seated position.
3.) Overhead Stretch: Raise both hands straight up over your head. Use one hand to grab the wrist of the opposite hand and gently pull to one side. Hold the stretch for 15 seconds, and repeat with the other arm.
4.) Shoulder Stretch: Bring your right hand over your left shoulder. Then place your left hand behind your right elbow and gently pull your elbow toward your body. Hold the stretch for 15 seconds and repeat with the other arm.
5.) Neck Roll: Relax your neck and shoulders. Then drop your right ear to your right shoulder and gently roll your head forward and to the other side, holding each position about 5 seconds. Repeat 5 times.