Hey there, glad to hear you're back on the bike. I had been riding a hybrid for years .....I upgraded to a road bike with drop handlebars about 6 weeks ago. I immediately began having hand pain and wrist numbness, so bad that my rides were limited to 15". I took the bike back to my LBS and they adjusted the handlebars and grips. I also bought a new pair of gloves with much more padding, and became more aware of not resting all my weight on my hands, and holding myself more upright. The pain and numbness is gone, and I am riding for an hour 3-4 times per week. Good luck to you!

Improper pressure on your ulnar nerve. Multiple possibilities. A change in bike fit caused by a change in the rider and/or a change in the bike itself. I can almost guarantee you it's the weight change, though.

More weight is on your wrist/hand and compressing the nerve. Shift weight balance to your backside (more upright biking position). This will take some stress off your wrists/hands.

My best recommendation is put bullhorns on the bike and/or change out the handlebars (consult a bike shop). Change hand positions frequently. Preferably, set the sections higher so your weight shifts back. Regardless, as you approach pre-injury weight the pain will subside.

Other alternatives: Shorten your reach by using a shorter stem or possibly raising your handlebars. On the more drastic (and costly end) you can consider a recumbent bike. Recumbents take the stress off your upper body, including hands.

Gloves are for protection and grip but not so much for comfort. You may find that you want a set of light, fingerless gloves to give you grip on bullhorns or other areas of the handlebars. The tiny bit of padding will dampen vibration as a bonus (gel is mostly a gimmick, as it is on saddles).