I have what I believe is great advice in the absence of a teacher. I am a comeback player like yourself and others here. While my last time with a horn was only 30 years ago (God bless you), I have been on the comeback trail for about one full year. Some of what I am going to tell you is advice I have read or been told personally and did not believe but now know is true.
I suspect at nearly 48 I am younger than you, given that you have been away from the horn my entire life. But the following is still true: do not be hard on yourself and give yourself time. Be patient. I have been feeling (and still do) that my entire trumpet life has passed me by while I worked and raised a family. As a result, I have been way, way too impatient to do it all and get it all in. I did a couple of stupid things I am just now recovering from and have gotten back on track.
If I was without a teacher, I would go through the Rubank series of books, from beginning to advance. Each lesson is a planned program of study that includes all the basics, i.e., long tones, lip slur, arpeggios, etc. The lessons are in a natural progression. I absolutely love it for that reason. When asked what people should practice, all the basic elements are in the Rubank series, within each lesson. It usually takes me 30 minutes in the beginning then as I consolidate and master the lesson, it then goes down to 20 minutes. Then, you can take a break as you do, or continue with your other etudes. Each lesson can take one to two weeks to master it is up to you.
I have read through an entire library of recommended trumpet books and if you are going to do it yourself. I recommend Herbert L. Clarke’s “Elementary Studies” and “Technical Studies” as well as Sigmund Herring’s Etudes. The reason is that Clyde Hunt has produced CDs from these books that allow you to listen how something should sound and then you can give it a go. Mr. Hunt has also produced several educational CDs in “call” and “response” fashion so you can teach yourself under his guidance.
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As for the swollen or tired lips, it is normal. Constant, steady practice will delay the onset time for lip fatigue. But, you must be patient as progress in that area in incremental.
I hope this helps.